Obsolete: It's now better to use <ref name="S1"/> instead of this template, because the ref tag will cause the reference to link back to the point in the text where you inserted the ref tag.
Examples of use: {{cite|S1}} or {{cite|S1|1880 Census}}. The first parameter is the citation number; e.g., S1. The optional second parameter is the name that you want to appear in the link text, which defaults to the citation number. This template also works for referencing notes and images. The citation links will be automatically renumbered if a source is added or removed.