Footnotes go at the bottom of the page where the reference occurs.
Within the essay text: put the note number at the end of the sentence where the reference occurs, even if the cited material is mentioned at the beginning of the sentence.
The note number goes after all other punctuation.
Be sure to use Arabic numerals (1, 2, 3) not Roman (i, ii, iii).
Single space each entry; double space between entries.
Indent the first line of each note.
Never reuse a number - use a new number for each reference, even if you have used that reference previously.
Use a shortened form examples for sources you refer to more than once.
To cite multiple sources in a single note, separate the two citations with a semicolon. Never use two note numbers at the end of a sentence.
The use of ibid. is now discouraged in favor of shortened citations.
To reduce the bulk of documentation in scholarly works that use footnotes or endnotes, subsequent citations of sources already given in full should be shortened whenever possible
Basic structure of the short form
The most common short form consists of the last name of the author and the main title of the work cited, usually shortened if more than four words, as in examples 4–6 below. For more on authors’ names, see (14.32). For more on short titles, see (14.33). For short titles for articles, see (14.185).
1. Samuel A. Morley, Poverty and Inequality in Latin America: The Impact of Adjustment and Recovery (Baltimore: Johns Hopkins University Press, 1995), 24–25.
2. Regina M. Schwartz, “Nationals and Nationalism: Adultery in the House of David,” Critical Inquiry 19, no. 1 (1992): 131–32.
3. Ernest Kaiser, “The Literature of Harlem,” in Harlem: A Community in Transition, ed. J. H. Clarke (New York: Citadel Press, 1964).
4. Morley, Poverty and Inequality, 43.
5. Schwartz, “Nationals and Nationalism,” 138.
6. Kaiser, “Literature of Harlem,” 189–90.
MORE INFORMATION ON JOURNAL ARTICLES SEE (14.185).
On subsequent references to journal articles, the author’s last name and the main title of the article (often shortened) are most commonly used. In the absence of a full bibliography, however, the journal title, volume number, and page number(s) may prove more helpful guides to the source.
1. Daniel Rosenblum, “Unintended Consequences of Women’s Inheritance Rights on Female Mortality in India,” Economic Development and Cultural Change 63, no. 2 (January 2015): 223, https://doi.org/10.1086/679059.
2. Rosenblum, “Female Mortality in India,” 225.
3. Rosenblum, Economic Development and Cultural Change 63:225.
The page numbering for Economic Development and Cultural Change is continuous throughout a single volume. Where that is not the case, the short form should include the issue number in addition to the volume number (i.e., “63 (2): 225”).
Taken from the Chicago Manual of Style 17th edition