This page, Help:Reftags, explains the use of the reftag element, "<ref>...</ref>" for defining reference footnotes, as displayed by using a <references /> tag or a "((Reflist))" template to list the footnotes. A reftag can also be defined by using wikitext function "((#tag:ref|...))" to generate the text "<ref>...</ref>" and allow direct use of subst'ing of templates to embed equivalent markup inside a footnote.
The general format is
<ref>text</ref> for a simple reftag footnote. However reftags can have a
name="xx" to define a footnote to be reused on a page by named ref,
<ref name="xx"/>, as when citing the same webpage at several spots in the article text.
There can be more than 3,000 reftag footnotes defined on a page, but usually there are less than a hundred.[fn 1]
When citing different pages in a single source, a named ref can be followed by a ((R)) template. Given a ref like "
<ref name="author1990">book</ref>", the ref "
author1990" can be reused, now using a different page number, say 53. This subsequent ref
((R|author1990|p=53)) will show the same superscript number, with a suffix of a colon and, in this case 53, the page number.: 53 This format allows the reader to click to the reference section, and then click on other references from the same source.
Rather than define hundreds of footnotes in a single list, various reftags could split to some named groupings, such as using "
<ref group="gg">...</ref>"" to collect those footnotes into group name "gg" as displayed by "
<references group="gg"/>".[fn 2] For example, a common tactic is to define footnote group "fn" which shows each link as "[fn 9]" for the 9th footnote in the
group="fn". A group name can be multiple words in ".." or in apostrophes (
group='set xx yy'), but a single-word name can omit the quotation marks or apostrophes (as:
group=fn). Hence, many group names are typically one-word labels, to avoid excessive apostrophes or quotation marks.[fn 3]
Rather than using an element "<ref>text</ref>", an alternate method is to use the wikitext function tag:ref, as "((#tag:ref|...text...))" to define the contents of a footnote.