Help:Citation Style 1

Citation Style 1 (CS1) is a collection of reference citation templates that can be modified to create different styles for different referenced materials. Its purpose is to provide a set of default formats for references on Wikipedia. It includes a series of templates that in turn use Module:Citation/CS1.

The use of CS1 or of templates is not compulsory; per WP:CITESTYLE:

"Wikipedia does not have a single house style. Editors may choose any option they want; one article need not match what is done in other articles or what is done in professional publications or recommended by academic style guides. However, citations within a given article should follow a consistent style."

WP:CITEVAR additionally states:

"If the article you are editing is already using a particular citation style, you should follow it; if you believe it is inappropriate for the needs of the article, seek consensus for a change on the talk page."

CS1 uses (in addition to Wikipedia's own Manual of Style) elements of The Chicago Manual of Style and the Publication Manual of the American Psychological Association, with significant adaptations.

Style
There are a number of templates that use a name starting with cite; many were developed independently of CS1 and are not compliant with the CS1 style. There are also a number of templates that use one of the general use templates as a meta-template to cite a specific source.

To be compliant with CS1, a template must:
 * Use Module:Citation/CS1 or one of the templates listed below.
 * Use a period as a punctuation mark to separate fields and end the citation.
 * Use a semicolon as a punctuation mark to separate authors and editors.
 * Format the title of longer works in italics.
 * Format the title of short works such as chapters in quotes.

General use
The following is a list of templates that implement Citation Style 1 for one or more types of citations but are not restricted to any specific source.

Specific source
There are a number of templates that are CS1 compliant, because they use a CS1 template as a base, but are tied to a specific source; these are listed in Category:Citation Style 1 specific-source templates.

How the templates work
CS1 uses a series of templates that provide a consistent output. The main difference is in parameters optimized for the subject. For example, cite book has fields for title and chapter, whereas cite journal has fields for journal and title.

This help page uses the names most commonly used across the templates series; see each template's documentation for details.

CS1 templates present a citation generally as:
 * With author:


 * Without author:

(where "n.d." could also be any other valid date formatted per the MOS)

Authors
An author may be cited using separate parameters for the author's surname and given name by using last and first respectively. If a cited source has multiple authors, subsequent authors can be listed in the citation using last2 and first2, last3 and first3, etc. For symmetry with the other numbered parameters, last1 and first1 are available as well, as shown in the following example:





For symmetry with similar parameters for editors and other contributors (discussed further below), longer parameter forms are also available for authors: author-last and author-first, as well as numbered variants like author-lastn and author-firstn or authorn-last and authorn-first (with n referring to this author's number in the list). Because the shorthand parameters might erroneously have been used also for editors and other types of contributors by some Wikipedians in the past, please make sure that the parameters actually refer to authors when expanding last and first parameters to their longer equivalents (equivalent parameters for editors etc. exist as well, see below).

If a cited source has a large number of authors, one can limit the number of authors displayed when the citation is published by using the display-authors parameter as described in detail in the Display options section of this help page.

If a cited author is notable and the author has a Wikipedia article, the author's name can be linked with author-link. If a citation includes multiple notable authors, one may use author-linkn or authorn-link, etc. This method is used because the last- and first-type parameters do not allow wikilinking. However, author-link cannot be used to link to an external website; the external link will not render correctly. Below is an example of a wikilinked author credit:





When an author is cited, the date of the cited work is displayed after the author's name, as shown in the example below:





If no author is cited, the date appears after the title, as shown in the example below:





If the cited source does not credit an author, as is common with newswire reports, press releases or company websites use:


 * author

This HTML comment alerts fact-checking and citation-fixing editors, and potentially bots, that the cited source did not name an author—the author was not overlooked. Without this entry editors and bots would waste time researching cited sources for a non-existent author credit.

When using author avoid citations like, unless the article is on a field in which the majority of professional journals covering that field use such a citation style.

Editors should use an author organizational citation when the cited source, such as a committee report, specifically names an official body or a sub-unit of the publisher as the collective author of the work, e.g. Commission on Headphone Safety or Rules Sub-committee. Do not use author to assert what you think was probably the collective author when the source itself does not specifically specify a collective author; doing so is original research and falsification of source verifiability and reliability.

author should never hold the name of more than one author. Separate individual authors into enumerated individual authorn parameters.

Editors
An editor may be cited using separate parameters for the editor's last and first name. A single or first editor would use editor-last and editor-first; subsequent editors would use editor2-last and editor2-first, editor3-last and editor3-first, etc.

If an editor has a Wikipedia article, you may wikilink to that Wikipedia article using editor-link. If a cited work has multiple editors, you may use editor2-link, editor3-link, etc. to wikilink to each editor's Wikipedia article. This method is used because editor-last and editor-first do not allow wikilinking. editor-link cannot be used to link to an external website.

If a cited source has a large number of editors, one can limit the number of editors displayed when the citation is published using the display-editors parameter as described in detail in the Display options section of this help page.

Translators
A translator may be cited using separate parameters for the translator's last and first name. A single or first translator would use translator-last and translator-first; subsequent translators would use translator2-last and translator2-first, translator3-last and translator3-first, etc.

If a translator has a Wikipedia article, you may wikilink to that Wikipedia article using translator-link. If a cited work has multiple translators, you may use translator2-link, translator3-link, etc. to wikilink to each translator's Wikipedia article. This method is used because translator-last and translator-first do not allow wikilinking. translator-link cannot be used to link to an external website.

Others

 * others: This parameter is used to credit contributors other than an author or an editor, such as an illustrator. You should include both the type of contribution and the name of the contributor, for example Illustrated by John Smith.

Dates
Dates are indicated by these parameters: When a source does not have a publication date, use n.d. or nd
 * date: Full date of publication edition being referenced, in the same format as other dates in citations in the same article. Must not be wikilinked.
 * or: year: Year of publication edition being referenced. Discouraged in favor of date, except in the rare case that  of the following conditions are met:
 * the publication-date format in the template is YYYY-MM-DD
 * the citation requires a  disambiguator
 * orig-date: Original publication date or year, for display (in square brackets) after the date (or year). For clarity, please supply specifics, for instance  or  . This parameter displays only if there is a value for date (or year). Alias: origyear.

Acceptable date formats are shown in the "Acceptable date formats" table of the. Further points:
 * Prescriptions about date formats only apply when the date is expressed in terms of Julian or Gregorian dates, or which use one of the seasons (spring, summer, autumn or fall, winter). Sources are at liberty to use other ways of expressing dates, such as "spring/summer" or a date in a religious calendar; editors should report the date as expressed by the source. Although the seasons are not normally capitalized, they are capitalized when used as dates in CS1 templates, and the capitalization of the season stated by the source may be altered to follow this convention. In cases where the date as expressed in the source is not compatible with the template software, the citation should be created without using a template.
 * Do not wikilink.
 * Access and archive dates in references should be in either the format used for publication dates, or YYYY-MM-DD.

Date format compliance with Wikipedia's Manual of Style
CS1 uses (MOS:DATEFORMAT) as the reference for all date format checking performed by Module:Citation/CS1. For various reasons, CS1 is not fully compliant with MOS:DATEFORMAT. This table indicates CS1 compliance with the listed sections of MOS:DATEFORMAT.

Date range, multiple sources in same year
If dates are used, the year range is 100 to present without era indication (AD, BC, CE, BCE). In the case where the same author has written more than one work in the same year, a lower-case letter may be appended to the year in the date parameter (date&#61;July 4, 1997b) or the year parameter (year&#61;1997b).

Auto-formatting citation template dates
Citation Style 1 and 2 templates automatically render dates (date, access-date, archive-date, etc.) in the style specified by the article's or  template. Editors may also choose how CS1/CS2 templates render dates by the use of &lt;keyword> in the article's template. Example: to have the CS1/CS2 templates in an article render their publication dates in the long form (fully spelled-out month names) with access-/archive-dates rendered in short form (abbreviated month names), write:

This documentation page has  at the top of this section so this cs1 template will render with ymd dates:

This global setting may be overridden in individual CS1/CS2 templates by use of df; abbreviated date forms are not supported by df.

Nota bene: CS1/CS2 auto-date formatting does not apply when previewing an article section that does not contain a template.

Titles and chapters

 * title: The title of the cited source. Titles are displayed in italics, except for short works such as a and cited articles in, , , , , and , where the title is shown in quotation marks. Use title case unless the cited source covers a scientific, legal or other technical topic and sentence case is the predominant style in journals on that topic. Use either title case or sentence case consistently throughout the article. Do not omit a leading "The" from the title. Subtitles are typically separated from titles with ": " though " – " is also used. As with trademarks, Wikipedia  attempt to emulate any stylistic flourishes used by the cited source's publisher, such as ALL-CAPS, all-lower-case, , etc.; use either standard title case or sentence case consistently. If the cited source is itself notable and has a Wikipedia article, the title can be wikilinked. Wikilinking the title will make it impossible to use the "url" parameter to link to an external copy of the cited source, so only do this when citing works that do not need to be externally linked. A link to the actual source is preferred to a link to a Wikipedia article about the source.
 * script-title: Languages that do not use a Latin-based alphabet, Arabic, Chinese, Cyrillic, Greek, Hebrew, Japanese, Korean, etc., should not be italicized and may also read right-to-left (RTL). To include titles in these languages, use script-title. Titles in script-title are wrapped in special HTML markup to isolate RTL script from adjacent left-to-right text.  Part of that special markup is a language attribute that browsers can use to assist in the proper display of the script.  Editors must add a prefix to the script that will identify the language.  The prefix is one of the supported language codes followed by a colon: ar: العربية.  Unrecognized codes are ignored and will display in the rendered citation.
 * trans-title: If the cited source is in a foreign language, an English translation of the title can be given here. This field will be displayed in square brackets after the title and will be linked to url if used.
 * chapter: The title of the cited chapter from the source, written in full. Displayed in quotes before the title. For websites arranged in sections the "at" parameter serves a similar function: Featured News
 * script-chapter: Languages that do not use a Latin-based alphabet, Arabic, Chinese, Cyrillic, Greek, Hebrew, Japanese, Korean, etc., may possibly read right-to-left (RTL). To include chapter titles in these languages, use script-chapter. Chapter titles in script-chapter are wrapped in special HTML markup to isolate RTL script from adjacent left-to-right text. Part of that special markup is a language attribute that browsers can use to assist in the proper display of the script.  Editors must add a prefix to the script that will identify the language.  The prefix is one of the supported language codes followed by a colon: ar: العربية.  Unrecognized codes are ignored and will display in the rendered citation. This field will be displayed following the transliterated title.
 * trans-chapter: If the cited source is in a foreign language, an English translation of the cited chapter title can be given here. This field will be displayed in square brackets within the quotation marks which enclose the chapter field.

Titles containing certain characters will both display and link incorrectly unless those characters are replaced or encoded like this:

|script-&lt; param >= language codes
Language codes known to cs1|2 for languages that do not use a Latin script are:

Type

 * type: Specifies the type of work cited. Appears in parentheses immediately after the title. Some templates use a default that can be overridden; example: cite press release will show "(Press release)" by default. Other useful values are: Review, Systemic review, Report, Abstract, Meta-analysis, Original article, Oral history, Email, Website, Text, Document. Alias: medium, in cite AV media, where typical values are: Motion picture, Moving image, Television production, Videotape, DVD, Blu-ray, Trailer, CD, Radio broadcast, Podcast, Sound.

Work and publisher

 * work: Used by some templates such as cite web (where it is aliased to website), cite news (aliased to newspaper), cite magazine (aliased to magazine), cite journal (aliased to journal), and others where the citation is usually to a specific item (given in the "title" parameter) found in a larger work (this "work" parameter), most commonly an article in a website or print periodical, or an episode in a TV series., which is for the publishing company. If the work is notable and has an article in Wikipedia, it should be wiki-linked at first appearance in citations in the article. If the "title" is already linked-to externally, do not externally link to the "work". If the work title as given by the site/publication would be exactly or substantially the same as the name of the publisher, do not use the "publisher" parameter (see below for more detail).
 * On websites, in most cases "work" is the name of the website (as usually given in the logo/banner area of the site, and/or appearing in the of the homepage, which may appear as the page title in your browser tab, depending on browser). Do not append ".com" or the like if the site's actual title does not include it (thus Salon, not  ). If no clear title can be identified, or the title explicitly is the domain name, then use the site's domain name. Do not falsify the work's name by adding descriptive verbiage like "Website of [Publisher]" or "[Publisher]'s Homepage". Capitalize for reading clarity, and omit "www.", e.g. convert "www.veterinaryresourcesuk.com" to "VeterinaryResourcesUK.com".
 * Many journals use highly abbreviated titles when citing other journals (e.g. J Am Vet Med for Journal of the American Veterinary Medical Association) because specialists in the field the journal covers usually already know what these abbreviations mean. Our readers usually do not, so these abbreviations should always be expanded.
 * If the titled item being cited is part of some other larger work, as in a book in a series, a special issue of a periodical, or a sub-site at a domain (e.g., you are citing the law school's section of a university's website system), it is usually better to use the name of that more specific work than just that of the entire larger work. Various citation templates provide separate fields for such information, e.g. chaptertitlevolumeseries in . If the nature of the work and its relation to the site, book, or other context in which it is found is complicated or confusing, simply explain the situation after the citation template and before the c that closes the citation.


 * publisher: the name of the organization that actually published the source. The field should not include the corporate designation such as "Ltd" or "Inc.", unless some ambiguity would result or the organization is usually known with that designation even in everyday use (e.g. Apple Inc., which otherwise might be confused with Apple Records and other publishers). "Publisher", "Publishing" and "Publications" can be abbreviated "Pubr.", "Pubg." and "Pubs." respectively, but some templates in this series include a period (full-stop) immediately after this parameter, so the period may have to be omitted; check the output if you abbreviate here. They are usually safe to omit, but are usefully included where the publisher's name might be confusing without it. This is most often the case when the publisher's name is something like "Joshua Martin Publications", which without the designation might be mistaken for a co-author/editor. A leading "The" can generally be omitted, again unless confusion might result (e.g., for The International Cat Association, "The" is part of their official acronym, TICA). If the publisher is notable and has an article independent of the "work", the "publisher" parameter can include a wiki-link to that article, but should never externally link to the publisher's website. Whether the publisher needs to be included depends to an extent on the type of work and sometimes on its recognizability. WP:Citing sources, and most off-Wikipedia citation guides, suggest that it should be used for books (even famous ones), but not necessarily other works. The "publisher" parameter should not be included for widely-known mainstream news sources, for major academic journals, or where it would be the same or mostly the same as the work. For example, the "publisher" parameter should be omitted in these examples:
 * Amazon.comAmazon Inc.
 * The Aberdeen TimesThe Aberdeen Times
 * The New York TimesThe New York Times Company
 * USA TodayGannett Company
 * NatureNature Research
 * If the work is self-published, this is a very important fact about potential reliability of the source, and needs to be specified; no consensus exists for the exact value of publisher in such a case, but some printed style guides suggest "author", while many Wikipedia editors have used "self-published" for increased clarity. When an exhaustive attempt to discover the name of the publisher (try whois for websites, and WorldCat for books, etc.) fails, use publisher to explicitly indicate that this was checked, so other editors do not waste time duplicating your fruitless efforts. Do not guess at the publisher when this information is not clear. See next entry for co-published works and how to specify multiple publishers and their locations.


 * location (alias publication-place): Geographical place of publication ( where you found your copy, nor location of material in the source). This is usually City, Country, or City, US State. The city name by itself can be used for world-recognized cities like New York, London (except in articles about Canadian topics), Paris, Tokyo. Simply having a unique name does not mean it is globally recognizable; e.g., many people do not know where Mumbai is, especially if they are old enough that it was called Bombay for much of their lives. If in doubt, be more not less specific, since "Toronto, Canada" and "San Francisco, California" do not actually hurt anything. Be more specific when a City, Country would be ambiguous, e.g. Hanley, Staffordshire, UK, versus Hanley, Worcestershire, UK. Do not use sub-national postal abbreviations ("DE", "Wilts", etc.), per MOS:POSTABBR. The location parameter should be omitted when it is implied by the name of the work, e.g. The Sydney Morning Herald. The location parameter should be used when the location is part of a common appellation of but not the actual title of a periodical. For example, the newspaper sometimes called the New York Daily News is actually Daily News and can be entered with Daily News New York, which yields: Daily News. New York. A similar example is The Times of London (contrast The New York Times). Per WP:SAYWHEREYOUGOTIT, provide the location of the edition you are using (e.g., if a publisher has operations in both New York and London and you have the London-published edition, use London, even if the publisher's corporate HQ is in New York). If your edition specifically gives multiple locations, this can be indicated with, e.g., New York / London. This same technique can be used for co-published works, e.g.: Oakbrook Terrace, Illinois / Los AngelesCouncil of Science Editors / Loyola Marymount University Press; just get them in corresponding order in both parameters. The templates do  have separate !mxt=y, !mxt=y, etc., parameters.  For historical publications that are still worth citing and still findable (e.g. via book digitizers – see the "via" parameter below), do not confuse the  (printing press owner-operator) with the  (organization or person that sponsored the work); an edition may have a printer's name in larger type than the publisher, but for citation purposes we care about the publisher. If the distinction cannot be determined for certain in a particular case, list both. While some off-site publishers lean toward omitting publishing locations, they can serve more than purely bibliographical purposes on Wikipedia (e.g. an overabundance of material published in one place in an article about another place may reveal an editorial bias).
 * publication-date: Date of publication when different from the date the work was written. Displays only if date or year are defined and only if different, else publication-date is used and displayed as date. Use the same format as other dates in the article; do not wikilink. Follows publisher; if work is not defined, then publication-date is preceded by "published" and enclosed in parenthesis.
 * via (optional): Name of the content deliverer (when they are the publisher). "via" is not a replacement for "publisher", but provides additional detail. It may be used when the content deliverer presents the source in a format other than the original, or when the URL provided does not make clear the identity of the deliverer, or as suggested in WP:The Wikipedia Library, e.g. WP:Credo accounts/Citations.  See also . Typical uses of this parameter are identification of a book-scanning and -databasing project such as those provided by the Internet Archive, Project Gutenberg, and Google Books; journal indexing and search services through which we commonly find academic articles, e.g. PubMed Central, Paperity, and JSTOR; and other aggregators or indexers of previously-published content, such as Dictionary.com. Use via only when a standard identifier cannot be used (see ). Example:

Pages
An editor may use any one of the following parameters in a given citation to refer to the specific page(s) or place in a cited source that contains the information that supports the article text. If more than one of the following parameters are used in the same citation, the error message Extra  or   ( help ) will display in the published citation. When more than one of the following parameters is used in error, page overrides both pages and at; pages overrides at. To resolve the error, remove extra parameters of this type until only one remains in the affected citation. If the same source is reused with different pages, separate citations must be created. A way around this problem is to use a short citation, or to provide linked page number citations.
 * page: page in the cited source containing the information that supports the article text, for example 52.
 * Note: For a hyphenated page, use 1234. This will not only properly display a hyphen, but also reduce the likelihood that an editor/bot will convert this to 1234 by mistake.
 * pages: pages in the cited source containing the information that supports the article text. Separate page ranges with an en dash: –, for example 236–239. Separate non-sequential pages either with commas or semicolons, for example 157, 159. The form 461, 466–467 is used when you are citing both non-contiguous and sequential pages. For page numbers higher than 999, either do not use thousands separators or enclose the page number in accept-this-as-written markup to avoid commas being erroneously interpreted as list separators, e.g. ((1,2341,235)). For multiple hyphenated pages, use the accept-this-as-written markup to avoid the hyphens being converted to dashes, e.g. ((12)), ((34)).
 * Note: CS1 citations do not record the total number of pages in a cited source; do not use this parameter for that purpose.
 * at: place in the cited source containing the information that supports the article text when a page number is not given, is inappropriate or is insufficient. Common examples include column or col., paragraph or para. and section or sec. Depending on the source being cited, other indicators may be appropriate to use with the at parameter including, but not limited to, track, hours, minutes and seconds, act, scene, canto, book, part, folio, stanza, back cover, liner notes, indicia, colophon, dust jacket, etc. Examples include Column 2 or Paragraph 5 or Back cover or Act III, Scene 2.
 * quote-page: The number of a single page quoted in quote. Use either quote-page or quote-pages, but not both. Should be a subset of the page(s) specified in page, pages or at. Displays preceded by p. unless yes. If hyphenated, use hyphen to indicate this is intentional (e.g. 312). Alias: none.
 * OR: quote-pages: A list or range of pages quoted in quote. Use either quote-page or quote-pages, but not both. Should be a subset of the pages specified in pages or at. Separate using an en dash (–); separate non-sequential pages with a comma . Displays preceded by pp. unless yes is defined. Hyphens are automatically converted to en dashes; if hyphens are appropriate because individual page numbers contain hyphens, for example: pp. 3-1–3-15, use double parentheses to tell the template to display the value of quote-pages without processing it, and use hyphen to indicate to editors that a hyphen is really intended: ((31–315)). Alias: none.

Edition identifiers

 * edition: Identifies the particular edition of a cited source when the source has more than one edition, such as "2nd", "Revised", etc. Note that this parameter automatically displays " ed." after your entry. For example, Revised third displays as: Revised third ed. The edition parameter can be omitted if there is no content difference between two editions of the same work; e.g. if a book was identically published in the UK and the US except, for example, ISBN number and cover art, it is not necessary to indicate either "UK" or "US" edition; or if citing minute:seconds of a film available in both a regular edition and a "Special Limited Collector's Edition", if the running time and cut are the same, it is not necessary to cite the particular edition.
 * series: When the source is part of a series, such as a book series or a journal where the issue numbering has restarted. For journal series, series should be limited to Original/New Series, First/Second/Third/... Series, or similar.
 * volume: For a source published in several volumes. This field is displayed in bold after the title and series parameters. An alternative is to include the volume information in the title parameter after the main title. Separate volume ranges with an en dash: –, for example I–IV. Separate non-sequential volumes either with commas or semicolons, for example I, III. The form I, III–V is used when you are citing both non-contiguous and sequential volumes. For volume numbers higher than 999, either do not use thousands separators or enclose the volume number in accept-this-as-written markup to avoid commas being erroneously interpreted as list separators.
 * issue: When the source is part of a series that is published periodically. Alias: number. When the issue has a special title of its own, this may be given, in italics, along with the issue number, e.g. 2,  Modern Canadian Literature . Please choose either issue or number depending on what nomenclature is actually used in a publication. If a publication carries both, issue and number designations (typically one being a year-relative and the other an absolute value), provide them both, for example 2 #143. Separate ranges with an en dash: –, and non-sequential numbers either with commas or semicolons. For numbers higher than 999, either do not use thousands separators or enclose the number in accept-this-as-written markup to avoid commas being erroneously interpreted as list separators.

Using |format=
When MediaWiki encounters an external link URL with a '.pdf' or '.PDF' extension, it renders the external link with a [//example.com/document.pdf PDF icon] in place of the usual [//example.com/document external-link icon]. To make rendered cs1|2 citations that link to PDF documents somewhat more accessible, cs1|2 automatically adds a parenthetical PDF annotation so that those readers using screen-reader technology can know the type of the linked file. This is imperfect because some on-line sources redirect .pdf URLs to .html landing pages (this is common for PDF documents behind paywalls or registration barriers). Because the parenthetical PDF annotation happens automatically, editors are not required to set PDF, though doing so causes no harm. The PDF parameter may be deleted as part of a more substantial edit but editors should consider that many cs1|2 templates are copied from en.Wikipedia to other-language Wikipedias when articles here are translated to that other language. Do not assume that other-language Wikipedias use up-to-date cs1|2 templates; many do not so removing PDF here can affect readers/translators at other Wikipedias.

Online sources
Links to sources are regarded as conveniences and are not required, except when citing Web-only sources. There are many digital libraries with works that may be used as sources.
 * Links should be to full versions of the source.
 * Online sources that require payment or subscription may be included per Verifiability.

Do not link to:
 * Sites that do not have permission to republish the work or which otherwise violate copyright.
 * Commercial sites such as Amazon, unless no alternative exists.
 * Reviews of the work.
 * Very short extracts such as Google Books snippet view where there is not enough context to verify the content, unless the entire work is also freely available there. (See WP:BOOKLINKS)

Link formats
Links should be kept as simple as possible. For example, when performing a search for a Google Book, the link for Monty Python and Philosophy would look like:
 * https://books.google.com/books?id=NPDgD546-doC&pg=PP1#v=onepage&q&f=false

But can be trimmed to:
 * https://books.google.com/?id=NPDgD546-doC&pg=PP1#v=onepage&q&f=false

or:
 * https://books.google.com/?id=NPDgD546-doC&printsec=frontcover

or:
 * https://books.google.com/?id=NPDgD546-doC (if Google Books does not provide the cover page).

Pages
A direct link to a specific page may be used if supported by the host. For example, the link to page 172 of Monty Python and Philosophy on Google Books:
 * https://books.google.com/?id=NPDgD546-doC&pg=PA172

like so:

Access date

 * access-date: The full date when the content pointed to by url was last verified to support the text in the article; do not wikilink; requires url; use the same format as other access and archive dates in the article's citations. It is not required for linked documents that do not change. For example, access-date is not required for links to copies of published research papers accessed via DOI or a published book, but should be used for links to news articles on commercial websites (these can change from time to time, even if they are also published in a physical medium). Note that access-date is the date that the URL was checked to not just be working, but to support the assertion being cited (which the current version of the page may not do). Can be hidden or styled by registered editors. Alias: accessdate.

Web archives
The original link may become unavailable. When an archived version is located, the original URL is retained and archive-url is added with a link to an archived copy of a web page, usually from services like WebCite and the Internet Archive. archive-date must be added to show the date the page was archived, not the date the link was added. When archive-url is used, url and archive-date are required, else an error will show. When an archived link is used, the citation displays with the title linked to the archive and the original link at the end:
 * archive-url. Alias: archiveurl.
 * archive-date. Alias: archivedate.
 * url-status: To change the order with the title retaining the original link and the archive linked at the end, set live:



When the original URL has been usurped for the purposes of spam, advertising, or is otherwise unsuitable, setting unfit or usurped suppresses display of the original URL (but url and archive-url are still required).

Identifiers
A custom identifier can be specified through

Anchors
The module creates HTML IDs by default suitable for use with shortened footnotes using the Harv- and sfn-family templates. These styles use in-text cites with a link that will jump to the ID created by the CS1 template. The ID is created from up to four author last names and the year, of the format.

ID: Creates a custom ID equivalent to the value ID. This is useful where the author and/or date is unknown. The template may be used here to create an ID for the Harv- and sfn-family templates.

Display options
These features are not often used, but can customize the display for use with other styles.

et al.
et al. is the abbreviation of the Latin et alii ('and others'). It is used to complete a list of authors of a published work, where the complete list is considered overly long. The abbreviation is widely used in English, thus it is not italicized per MOS:FOREIGN.

Accept-this-as-written markup
There are occasions where Module:Citation/CS1 emits error or maintenance messages because of, or makes changes to, the values assigned to a select set of parameters. Special markup can be used to enforce that a value will nonetheless be accepted as written. The markup for this is, i.e., wrap the entire parameter value in two sets of parentheses. Parameters that support this markup are:

Printing
When viewing the page, CS1 templates render the URL to the title to create a link; when printing, the URL is printed. External link icons are not printed.

Elements not included
Not all factually accurate pieces of information about a source are used in a Citation Style 1 citation. Examples of information not included:
 * The total number of pages in a cited source
 * The name of the library that provided access to an electronic copy of a cited source
 * The name of the library that owns a physical copy of a cited work
 * The library record or shelf location of a physical copy of a cited work

Tools
CS1 templates may be inserted manually or by use of tools:
 * Citoid, a tool built into Visual Editor that attempts to build a full citation based on a URL. See user guide.
 * RefToolbar is part of the editing tool bar. Version 2.0 does not yet support all templates supported by version 1.0.
 * ProveIt provides a graphical interface for editing, adding, and citing references. It may be enabled per the documentation.
 * Wikipedia DOI and Google Books Citation Maker
 * Reflinks Adds references to templates while updating/filling-in title/dates/publisher/accessdates etc.
 * reFill open source version of Reflinks
 * Zotero can export citations in Wikipedia-ready format.
 * Citer – generates shortened footnote or named reference for a given Google Books URL, ISBN, or DOI. Also supports some major news websites.

Error checking scripts:
 * User:Svick/HarvErrors is a script that may be enabled to display errors when using Shortened footnotes or parenthetical referencing. It does not warn when a long citation has been added but not a short one (using sfn or harvnb).
 * User:Trappist the monk/HarvErrors is very similar, but also contains additional warnings for potential issues.
 * User:BrandonXLF/CitationStyleMarker highlights inconsistent (CS1 vs CS2) citation styles used in the same article. Only works with templated citations.

Reliability scripts:
 * User:Headbomb/unreliable color codes URLs and DOIs in gray/red/pink/yellow depending on their broad reliability

TemplateData
This section documents interactions between WP:TemplateData and tools which use that data to edit Wikipedia such as VisualEditor and bots. Before making changes to the TemplateData be aware of these interactions.

User:InternetArchiveBot

 * If an argument is set to "required" the argument will be added to all templates edited by IABot. This including adding empty arguments. For example, when website is "required" IABot makes the following edit:.

Common issues

 * access-date does not show.
 * If url is not supplied, then access-date does not show; by design.


 * The bare URL shows before the title.
 * If the title field includes a newline or an invalid character then the link will be malformed; see Web links.


 * The title appears in red.
 * If URL is supplied, then the title cannot be wikilinked.


 * The URL is not linked and shows in brackets.
 * The URL must include the URI scheme in order for MediaWiki to recognize it as a link. For example:  vs..


 * A field is truncated.
 * A pipe in the value will truncate it. Use  instead.


 * The template markup shows.
 * Double open brackets &#91;&#91; are used in a field without closing double brackets &#93;&#93;.


 * The author shows in brackets with an external link icon.
 * The use of an URL in author-link will break the link; this field is for the name of the Wikipedia article about the author, not a website.


 * Multiple author or editor names are defined and one or more does not show
 * The parameters must be used in sequence, i.e. if last or last1 is not defined, then last2 will not show. By design.


 * page, pages or at do not show.
 * These parameters are mutually exclusive, and only one will show; by design.