Endnotes and Footnotes
Here’s a brief overview of how to do endnotes and footnotes (condensed from The Chicago Manual of Style).
Almost every work that is neither fiction nor personal experience relies on secondary sources (other publications on the same or related subjects) or on primary sources (manuscript collections, archives, contemporary accounts, diaries, books, personal interviews, and so on). Ethics, as well as the laws of copyright, requires authors to identify their sources, particularly when quoting directly from them.
Formats for documenting these sources vary from publisher to publisher. Most use one of two systems–endnotes or footnotes–sometimes accompanied by a bibliography.
Endnotes are placed at the back of a book, after any appendix material and before the bibliography. They are arranged by chapter. The chapter number or title or both must be given.
Most publishers prefer endnotes over footnotes, unless there are only one or two notes in the whole book. One advantage of endnotes is that the length of each note is not a great concern, since notes and text need not be jumbled about to make them fit on the same printed page.
References are cited in the text by number, rather than at the end of the book. The reference numbers in the text are placed in parentheses (12) or square brackets  or are set as superscript figures (12). The chief disadvantage of this system is that additions or deletions cannot be made without changing numbers in both text references and list.
Wherever possible, a note number should come at the end of a sentence, or at least of the end of a clause. Preferably, the note number follows a quotation, whether the quotation is short and run into the text or long and set off from the text. Occasionally it may be inserted after an author’s name or after text introducing the quotation.
Typed pages, including the footnotes, must all be the same length, and each footnote must appear on the same page as the reference to it. A manuscript peppered with footnote references may well be a typesetter’s nightmare.
A list of books and other references used by an author in a scholarly work may be placed at the end of the book, before the index. In a work containing many footnotes or endnotes, a bibliography in addition to the notes can be a useful device for the reader and an economical one for the author and publisher. Full particulars for each source need appear only in the bibliography; therefore, citations in the notes may be considerably shortened or abbreviated.
For detailed instructions on formatting endnotes, footnotes, bibliographies, see the guidelines in The Chicago Manual of Style. You can find samples of Chicago-style footnotes and bibliography at the CMS website: http://www.press.uchicago.edu/Misc/Chicago/cmosfaq/. Choose “Tools” from the menu, which will take you to “Examples of Chicago-Style Documentation.”