The mechanics of citing sources will vary from style to style, but there are two primary methods of giving citations: parenthetical (in-text) references and notes. Although most documentation styles provide guidelines for both in-text references and notes, each is generally identified with one or the other.

Notes

The citation of materials in footnotes (appearing at the bottom of the page) and endnotes (appearing at the end of the document, usually beginning on a separate sheet) is a more traditional method for identifying original sources. One advantage of giving citations in notes is that the reader will not be interrupted by sometimes lengthy references in the text. And now that word processors are able to manage the formatting of notes automatically, the writer no longer needs to set aside time to adjust the spacing of every page to accomodate them.

Unlike the parenthetical-reference styles, note-based styles do not require the appending of a list of sources. Instead, complete bibliographic information is provided in the first note that cites a work; subsequent notes referring to that work will use a shortened version of the citation. Therefore, the author need not worry about omitting any works from a list of sources, or accidentally including any that aren't actually referred to or quoted from.

The style established by the University of Chicago (commonly referred to as the Chicago style) is the most commonly used for notes, although the citation-sequence style adopted by the Council of Science Editors (CBE) and the Numbered References style both call for citations to appear in notes.