Wikipedia:Footnote

This page documents an English Wikipedia style guideline. It is a generally accepted standard that editors should follow, though it should be treated with common sense and the occasional exception. When editing this page, please ensure that your revision reflects consensus. When in doubt, discuss first on the talk page.

Shortcuts: WP:FN WP:FOOT WP:NOTES

A footnote is a note placed at the bottom of an article that expands on a specific portion of the text. The connection between that portion of the text and the corresponding footnote is indicated by a number or symbol in the text. Wikipedia has several mechanisms for creating footnotes that contain reciprocal hyperlinks; in other words, clicking on the number/symbol found in the main text brings one to the corresponding footnote, and vice versa.

Footnotes serve two purposes. First, they are used to add material that explains a point in greater detail, particularly if the explanation would be distracting if written out in the main article. Second, they are used to cite the reliable sources that support an assertion in the main article. This is known as an "inline citation". Two different types of footnotes may be used for these two different purposes, as described below.

The prevailing system for adding footnotes to an article involves the <ref> tag. This system has several advantages, including automatic sequential numbering of the footnotes and provisions for multiple references to the same footnote. To add such a footnote to an article, the editor includes the text of the footnote between two HTML-style tags, e.g. <ref>Text of footnote goes here.</ref>. Different classes of footnotes can be defined within an article using the "group" parameter inside the "ref" tag, as described below.

Editors may also use the older system of template-based footnotes, such as {{ref label}} and {{note label}}. These have the disadvantage that they are not numbered automatically; the editor has to choose a specific label. It is generally expected that footnotes will be labeled in the order in which they occur in the text. Therefore, if an editor adds such a template-based footnote in the middle of an article, the editor should also renumber/increment all the subsequent footnotes of the same type, by hand.

Footnotes are not the only way to cite sources. Alternative methods are embedded links and Harvard referencing (also known as author-date or parenthetical referencing). For more information, see Wikipedia:Citing sources, the main style guide on citations.

Citing sources is important for improving the quality of Wikipedia's articles. A key content policy, Wikipedia:Verifiability, says that any material that is challenged or likely to be challenged, including any contentious material about living people, and all quotations, must have a source. Unsourced or poorly sourced material may be removed from any article, and if it is, the burden of proof is on the editor who wishes to restore it.

How to use

A simplified explanation is given at Help:Footnotes

1. Place a <ref> ... </ref> where you want a footnote reference number to appear in an article—type the text of the note between the ref tags.
2. Place the <references /> tag or {{reflist}} tag in either a "Notes" or "References" section as explained in the Guide to Layout — the list of notes will be generated in that section. (The choice between {{reflist}} and <references /> is a matter of style; Wikipedia does not have a general rule.)

This page itself uses footnotes, such as the one at the end of this sentence.^[1] If you view the Wikicode of this page by clicking "Edit this page", you can see a working example of footnotes.

Ref tags and punctuation

Material may be referenced mid-sentence or at the end of a sentence or paragraph. When a reference tag coincides with punctuation, the reference tag is normally placed immediately after the punctuation, except for dashes, as recommended by the Chicago Manual of Style and other style guides.^[2][3] Some editors prefer the in-house style of journals such as Nature, which place references before punctuation. If an article has evolved using predominantly one style of ref tag placement, the whole article should conform to that style unless there is a consensus to change it.

Naming a ref tag so it can be used more than once

To give a footnote a unique identifier, use <ref name="name"> ... </ref>. You can then refer to the same footnote again by using a ref tag with the same name. The name cannot be a number, or the extension will return an error. The ref name need not be placed within quotes unless it contains a space or some non-ASCII characters (the wiki parser converts single word quoteless attribute values into validly quoted XHTML). Note that any quotation marks placed around the ref name must be straight quotes (") rather than curly quotes (“ or ”).

Named references are used when there are several cases of repetition of exactly the same reference, including the page number for books; they should not be used to cite different pages in the same book. Named references in wikitext serve a purpose similar to loc. cit. or ibid. in printed media. See also cautions in Style below.

Only the first occurrence of text in a named ref will be used, although that occurrence may be located anywhere in the article. You can either copy the whole footnote, or you can use a terminated empty ref tag that looks like this: <ref name="name" />. Such forward-slash-terminated named tags may precede the definition of the named reference.^[4] In subsequent uses of the named tag the use of <ref name="name" /> is encouraged rather than copying the whole footnote again, as whole footnotes tend to reduce the readability of the article's text in edit mode, which makes finding specific parts of the text when editing tedious.

In the following example, the same source is cited three times.

This is an example of multiple references to the same footnote.<ref name="multiple"/>

Such references are particularly useful when citing sources, if different statements come from the same source.<ref name="multiple">Remember that when you refer to the same footnote multiple times, the text from the first reference is used.</ref>

A concise way to make multiple references is to use empty ref tags, which have a slash at the end.<ref name="multiple">This text is superfluous, and won't show up anywhere. We may as well just use an empty tag.</ref>

== Notes ==

<references />

The text above gives the following result in the article (see also Notes section below):

This is an example of multiple references to the same footnote.^[5]

Such references are particularly useful when citing sources, when different statements come from the same source.^[5]

A concise way to make multiple references is to use empty ref tags, which have a slash at the end.^[5]

One should be particularly careful when deleting a named reference with text content, because the footnote text will be deleted unless it is copied to another ref tag with the same name.

Citation templates

Text placed between <ref> and </ref> may be short notes or full bibliographic references, and may be formatted either by hand or with the assistance of templates. Instructions on available templates to help format bibliographic references may be found at Wikipedia:Citation templates. Use of such templates is not required; see WP:CITE.

Previewing a single section edit

Notes and references not normally visible

When you edit a single section on a long page, the Notes or References section will not be visible when you preview your edits. Thus you ordinarily cannot see how your footnotes (text you place between <ref> and </ref> tags) will later appear when you save your edits.

Workaround for notes and references

A simple workaround is to temporarily insert a <references/> or {{reflist}} tag at the bottom of the edit box of the section you are editing. Your footnotes will appear at the bottom of your section so you can preview them. When you are satisfied with your edits to the section, delete your temporary <references/> or {{reflist}} tag, and save your edits. Now your footnotes should appear in the "Notes" or "References" section along with other footnotes on the page.

While you preview the footnotes in a section this way, the first footnote in the section will temporarily have a number of one (1), because the preview will not show footnotes from elsewhere on the page. The footnotes will renumber properly across the entire article after you save your edited section.

Re-use of reference(s) from another section

Another complication is that you will not be able to preview the effect of citing a footnote from another section merely by citing its name (for example: <ref name="multiple"/>). If the section you want to edit reuses footnotes from elsewhere on the page, a simple solution is to edit the whole page at once in order to preview the footnotes accurately.

If you want to avoid this, the only workaround would be to copy and temporarily insert the full code of the relevant reference(s) at the top of the edit box of the section you are editing. If you have used the "workaround for notes and references" (above) the footnotes will appear at the bottom of your section so you can preview them. When you are satisfied with your edits to the section, delete the temporary full reference code and save your edits. Now your footnotes should appear in the "Notes" or "References" section along with other footnotes on the page.

Separating reference lists and explanatory notes

It is often desirable for an article to list sources separately from explanatory notes. When this is done the sources may appear in an alphabetized list unlinked to the article (e.g., Starship Troopers) or in a list that is linked to specific text in the article (e.g., Jane Austen). A separate section containing references is usually given the title "References," while the explanatory notes section retains the "Notes" title.

One way to generate a linked list of sources involves the "group=" option of the <ref> tag, which is analogous to the "name=" option described above. In this approach, narrative references are given their own "group" namespace. The group identifier is specified inside explanatory note <ref> tags and its final <references/> tag. The closing tag </ref> does not change.

For example:

Example text,<ref group=nb>This is an example explanatory note</ref> more example text.<ref group=nb name=ex02>Explanatory notes can be shown separately from references or citations - giving a neater appearing alternative compared to having mixed "Notes and references" or "Notes and citations" sections. This is an example of such a note. It is generated via use of group extension of the reference tag.</ref> A point made with a supporting reference.<ref>Author, A. (2007). "How to cite references", New York: McGraw-Hill.</ref> A second appearance of a note.<ref group=nb name=ex02/> Example text here, see also known bugs.{{#tag:ref|A surprising footnote, which needs a reference of its own.<ref>Author, B. (1986) "How to cite a reference in a footnote", Melbourne: Totally Awesome Publishing Company.</ref>|group=nb}}

== Notes ==
<references group=nb/> 

== References == 
<references/>

Rendering:

In general practice note that footnotes that cite sources are not given a group identifier. This is because they are usually (by far) more numerous and more important to the quality of the article. Nothing special need be done for them; the usual methods, described above, will work as always. To maintain a separate list of scholarly footnotes, the group identifier "nb" or "note" is generally adopted.

It is also possible to use the reference templates, e.g., {{ref label}} and {{note label}} to separate a sources list from content notes. As with all citation styles, consensus should be achieved on the talk page before implementing such a change.

Style recommendations

• Do not use Ibid, op. cit. or similar abbreviations in footnotes. Other editors who add new references to the article may not take the time to correct Ibid references broken by their addition. Furthermore, not all readers are familiar with the meaning of the terms. If a reference is reused in more than one footnote, it is preferable to use the format "Smith, Short Title, 182" rather than "Ibid, 182", so as to avoid these problems, or use named references if appropriate.
• Consider maintaining a separate bibliography/references section that gives full publication details for frequently cited sources, then you only need to cite the author, short title, and page number in specific notes, following Wikipedia:Citing sources. For examples of this usage, see Johannes Kepler and Rabindranath Tagore. For another solution to this issue, especially when a single source is cited many times in one article, but cites to different pages in that source each time, see Template:Rp.
• The decision on whether or not to use quotes in footnotes, is primarily a decision of style and may vary from article to article. Citation templates include parameters for quotes, as quoting text can be useful for the verifiability of material in an article. Footnoted quotes are acceptable if they are brief, relevant to the article text that is being footnoted, compliant to copyright (including fair use where applicable), of use or interest to the reader, and not used as an evasion of other guidance (most notably: content policy).^[6] Where there is disagreement on the use of quotes in footnotes on a particular article, consensus should be sought on the talk page for that article.

Known bugs

• Internal links and wiki formatting work as normal within the text of the citation, like this: <ref>''[[Wikipedia]]'', [[18 March]], [[2007]].</ref> However, the "pipe trick" will not expand a link for you in ref text; you must type out [[George Clark (historian)|George Clark]], rather than just typing [[George Clark (historian)|]] and letting the software fill in the text after the pipe. See Help:Pipe_trick#Cite.php_footnotes_and_the_pipe_trick.
• When citing a website within the ref tags, include a name for the site inside the brackets for the URL. Unnamed URLs appear as numbers, so <ref>[http://www.google.com]</ref> results in the footnote being displayed as [1]; the reader clicks to the numbered footnote only to see another number. Thus, use a name in the link to display the website page title in the reference list, as in this example: <ref>[http://www.google.com Google]</ref> .
• References cannot be nested: <ref name="Ran1912">J. Random, 1912. Cited in <ref name="Foo2005"/></ref> does not render correctly.
  • This bug can be bypassed using the #tag magic word: use {{#tag:ref|J. Random, 1912. Cited in <ref name="Foo2005"/>|name=Ran1912}} instead.
• Avoid use of "subst", or at least verify that it works correctly. A Mediawiki bug prevents the expansion of certain (if not all) "subst"'s within refs.
• Template parameters do not pass to <ref> tags (for example, <ref>[http://{{{1}}}.htm Source]</ref> within template source code; see also mw:Extension:Cite/Cite.php#Current_problems and User:Pengo/pageusingref). Ref tags can be used in variables when a template is used, though (for example, {{taxobox}}'s status_ref parameter).
  • This bug can be bypassed using the #tag magic word: use <includeonly>{{#tag:ref|content|name=foo}}</includeonly> in the template instead of <ref name="foo">content</ref>.

Resizing references

Some editors prefer references to be in a smaller font size than the text in the body of the article. Although smaller text has some disadvantages, it is common when there is a long list of references (as a rule of thumb, at least ten) to replace the basic <references /> tag with {{Reflist}}, which reduces the text size to 90%. (Note: Do not use {{Reflist}} with a "subst:".) The underlying CSS class is "references-small", so an alternative is to use this directly: <div class="references-small"><references /></div>. If this class is used to make other sections at the bottom of the page ("Notes", "See also", "External links", etc.) small for consistency (this is rarely done), the div tags must be opened and closed within each section.

A similar CSS class exists to create small footnotes in two columns, but this displays as a single column in some common browsers (like Internet Explorer). If desired, use <div class="references-2column"><references /></div>

The same effect (with any number of columns) can be accomplished by using {{Reflist|number of columns}}.

Compatibility with other MediaWiki sites

As of late December 2005, the mw:Extension:Cite/Cite.php extension to MediaWiki has been installed on all Wikimedia wikis. Other wikis that use the MediaWiki software may not have this extension installed, and therefore may be unable to display Cite.php footnotes. The Special:Version page on any MediaWiki wiki shows the installed extensions.

Extensions like Cite/Cite.php are installed after installing MediaWiki software; these extension files are placed in the directory wiki/extensions/.

Caution on converting citation styles

An older system using {{ref}} and {{note}} templates is still common. Converting this older system^[7] to the new <ref>...</ref> system can make the references in an article easier to maintain.

Converting citation styles should not be done without first gaining consensus for the change on the article's talk page.

A December 2005 ArbCom case ruled that the following scripts could no longer be used by a certain Wikipedian:

• Wikipedia:Footnote3/numlink2note.pl, explained at Wikipedia talk:Footnote3/numlink2note.pl
• Wikipedia:Footnote3/order-footnote.pl, explained at Wikipedia talk:Footnote3/order-footnote.pl

Similarly, individual users may be forbidden to "manually convert citation styles on any articles."

So, tread lightly, and seek consensus first, before converting citation styles. For example, when using (semi-)bot tools as listed below:

• User:Cyde/Ref converter converts articles that use the {{ref}} and {{note}} system into the more recent mw:Extension:Cite/Cite.php system;
• Citation Tool diagnoses and fixes sequencing and duplication errors in Cite.php references. In the future, Citation Tool may (optionally) enable user-guided conversion of some or all of the <ref> numbered citations to named notes using the footnote3 template technology (which includes Harvard references).

CAUTION: do not edit-war with automated tools that convert in opposing directions.

See also

• Wikipedia:Verifiability, the relevant policy regarding what material should be cited
• Wikipedia:Citing sources, the relevant style guide.
• Wikipedia:Citing sources/example style, listing also several examples of non-numbered APA style and Harvard referencing techniques
• Wikipedia:Template messages/Sources of articles for complete list of templates that are available for citations; note that several of these templates can easily be combined with "footnote3" footnotes, see Gymnopédie#Notes and references for an example.
• Wikipedia:WikiProject Wikicite: Proposal for use of database of citations.
• Wikipedia:WikiProject Fact and Reference Check
• Other types of numbered footnotes:
  • Wikipedia:Footnote1, a very old, manually-numbered footnote system that should not be used.
  • Wikipedia:Footnote2, another obsolete system that should not be used.
  • Wikipedia:Footnote3, an automatically-numbered footnote system using templates, which is widely used but has been replaced by MediaWiki footnotes.
• Help:Footnotes
• mw:Extension:Cite/Cite.php (formerly at meta:Cite.php) - description of the <ref>...</ref>/<references/> system at metawiki
• meta:Biblio - Biblio.php, an extension of Mediawiki which provides a citation manager. (beta maturity)
• Wikipedia:Ref reform
• Bug 2745: Have References text edit window on Edit pages.
• Template:Rp - adds ability to handle Harvard-style page number citations to Cite.php inline references (intended for use when one source is cited a large number of times, and would produce either too many individual entries under <references /> for the same source, or one exceedingly long entry that cited too many pages to possibly be useful to readers).
• m:Wikicite an idea for standardizing how facts are cited.
• m:Wikicat is the bibliographic catalog used by the WikiTextrose project.
  • m:WikiTextrose, a text relationship database for mapping the various interactions between interpretable artifacts.
• Wikipedia:Referencing for beginners A simple practical guide to getting started.

Notes

1. ^ This footnote is used as an example in the "How to use" section.
2. ^ The Chicago Manual of Style, 14th ed. 1993, Clause 15.8, p. 494 - "The superior numerals used for note reference numbers in the text should follow any punctuation marks except the dash, which they precede. The numbers should also be placed outside closing parentheses." - See also CMoS Online, Style Q&A, Punctuation.
3. ^ Other style guides suggesting that superscript note reference numbers should generally be placed after punctuation include: Oxford/Hart's Rules, the MLA Style Manual, APA Style, Dictionary.com, IEEE style and Legal Blue Book Style (as well as the general exception for dashes, guides may variously make other exceptions for colons, semicolons and quotation marks).
4. ^ Wikipedia Signpost. November 13, 2006.
5. ^ ^{a b c} Remember that when you refer to the same footnote multiple times, the text from the first reference is used.
6. ^ For example, to work around the proscription placed on editors by Wikipedia:Neutral point of view#Attributing and substantiating biased statements.
7. ^ The Wikipedia:Footnote3 system created footnotes with the {{ref}}/{{note}} and the {{ref_label}}/{{note_label}} pairs of templates. The system may be encountered on many Wikipedia pages.

1. Additional references that are not created with <ref> ... </ref> WP:CITE#Footnotes, do not continue the numbering. These are mistakes; they should be corrected by converting them to footnotes using "ref" tags.