Help:Cite

See: Extension:Cite

The basic concept of the <ref> tag is that it inserts the text enclosed by the ref tags as a footnote in a designated section, which you indicate with the placeholder tag <references />. The new format cannot be used interchangeably with the old format — you must pick one or the other.

If you forget to include <references />in the article, the footnotes will not appear, but a red error message will be displayed at the end of the page.

Refer to the link above for detailed documentation on how to use the <ref> and <references /> tags.