Each citation style handles this situation a little bit differently! Here are specific examples of how it works in the three major citation styles:
APA Style
Per the APA Manual (6th edition), p. 178:
For In-Text Citations:
Arrange two or more works by the same authors (in the same order) by year of publication. Place in-press citations last. Give the authors’ surnames once; for each subsequent work, give only the date.
Training materials are available (Department of Veterans Affairs, 2001, 2003)
Past research (Gogel, 1990, 2006, in press)
Identify works by the same author (or by the same two or more authors in the same author) with the same publication date by the suffixes a, b, c, and so forth, after the year; repeat the year. The suffixes are assigned in the reference list, where these kinds of references are ordered alphabetically by title (of the article, chapter or complete work).
Several studies (Derryberry & Reed, 2005a, 2005b, in press-a; Rothbart, 2003a, 2003b)
(Stahl, 2011a)
(Stahl, 2011b)
For additional examples and tips on citing multiple sources by the same author in APA Style, check out the APA Style Blog’s posts on How to Cite Multiple Works by the Same Author in a Compilation and How to Cite Articles with the Same Authors and Same Year.
MLA Style
In the Works Cited (Per the MLA Handbook (8th edition), p. 113: To cite two or more works by the same author, give the name in the first entry only. Thereafter, in place of the name, type three hyphens, followed by a period and the title. The three hyphens stand for exactly the same name as in the preceding entry. This sort of label does not affect the order in which the entries appear; works listed under the same name are alphabetized by title.
For in-text citations (Per the MLA Handbook (8th edition), p. 55: Including only the author name and page number in a parenthetical citation is insufficient if more than one work appears under that author’s name in the work cited list. In that case, include a shortened version of the source’s title.
For example:
In-text citations:
(Haynes, Noah’s Curse 84)
(Haynes, The Last Segregated Hour 57)
Works cited (don’t forget to indent the second and subsequent lines):
Haynes, Stephen R. Noah’s Curse: The Biblical Justification of American Slavery. Oxford University Press, 2007.
—. The Last Segregated Hour: The Memphis Kneel-Ins and the Campaign for Southern Church Desegregation. Oxford University Press, 2012.
For additional examples and tips on multiple sources by the same author in MLA Style, check out the MLA Style Center’s “How do I distinguish works by an author that have the same title?”
Chicago Style
Per the Chicago Manual of Style (17th edition):
Notes and Bibliography method (see section 14.68: The 3-em dash for one repeated name for caveats please refer to 14.67).
For successive entries [in a bibliography] by the same author, editor, translator, or compiler, a 3-em dash (followed by a period or comma, depending on the presence of an abbreviation such as ed.) replaces the name after the first appearance.
For example: (don’t forget to indent the second and subsequent lines):
Judt, Tony. A Grand Illusion? An Essay on Europe. New York: Hill and Wang, 1996.
———. Reappraisals: Reflections on the Forgotten Twentieth Century. New York: Penguin Press, 2008.
In a bibliography, titles by the same author are normally listed alphabetically.
Author-Date References (see section 15.18: Chronological order for repeated names in a reference list)
For successive entries by the same author(s), translator(s), editor(s), or compiler(s), a 3-em dash replaces the name(s) after the first appearance. The entries are arranged chronologically by year of publication in ascending order, not alphabetized by title. Undated works designated n.d. or forthcoming follow all dated works.
For example: (don’t forget to indent the second and subsequent lines):
Schuman, Howard, and Jacqueline Scott. 1987. “Problems in the Use of Survey Questions to Measure Public Opinion.” Science 236:957-59.
———. 1989. “Generations and Collective Memories.” American Sociological Review 54:359-81.
Two or more works by the same author in the same year must be differentiated by the addition of a, b, and so forth (regardless of whether they were authored, edited, compiled or translated), and are listed alphabetically by title. Text citations consist of author and year plus letter.
Fogel, Robert William. 2004a. The Escape from Hunger and Premature Death, 1700-2100: Europe, America, and the Third World. New York: Cambridge University Press, 2004.
———. 2004b. ”Technophysio Evolution and the Measurement of Economic Growth.” Journal of Evolutionary Economics 14 (2): 217-21. Doi:10.1007/s00191-004-0188-x.
(Fogel 2004b, 218)
(Fogel 2004a, 45-46)
For additional information on citing multiple sources by the same author in Chicago style, please refer to the Chicago Manual of Style.
More information:
For further help please contact the Wolak Learning Center at 603.645.9606 (On-Campus Students) and Online Writing Center at 866.721.1662 (Online Students) for additional information.
This information is intended to be a guideline, not expert advice. Please be sure to speak to your professor about the appropriate way to cite multiple sources by the same author in your class assignments and projects.
References
American Psychological Association. (2010). Publication manual of the American Psychological Association. Washington, D.C.: American Psychological Association.
The Modern Language Association of America. (2016). MLA Handbook. New York: Modern Language Association of America.
University of Chicago. (2017). The Chicago Manual of Style. Chicago: University of Chicago Press.