A manual for writers of research papers, theses, and dissertations, 7th edition - Kate L. Turabian 2007

Notes - Footnotes versus endnotes
Notes-bibliography style: the basic form
Part II. Source Citation

Writers use several different kinds of notes, depending on their field, their readers, and the nature of their project. This section explains your options and how to choose among them.

16.3.1 Footnotes versus endnotes

Your department may specify whether you should use footnotes or endnotes, especially for a thesis or dissertation. If not, you should generally choose footnotes, which are easier to read. Endnotes force readers to flip to the back to check every citation. If you include substantive comments in endnotes (see 16.3.5), readers might ignore them because they cannot tell without turning back which notes are substantive and which only cite sources.

On the other hand, choose endnotes when your footnotes are so long or numerous that they take up too much space on the page, making your report unattractive and difficult to read. Also, endnotes better accommodate tables, quoted poetry, and other matter that requires special typography.

If you use endnotes, you can reduce the risk that readers will miss substantive comments by separating substantive notes from source notes. Number source notes and print them as endnotes. Signal substantive notes with asterisks and other symbols (see 16.3.3) and print them as footnotes. Do not do this if you have more than a few substantive notes.