If you write a sentence that quotes from several places in the same source and you wish to cite them in a single parenthesis, list the appropriate page numbers in the order they are quoted, separated by commas—
Acquiring a tattoo may be an act of “identity formation,” but as such it can be interpreted as a symptom of “profound self-doubt” (Friedman 27, 33).
It may be clearer, however, to break these up when possible—
Friedman claims that acquiring a tattoo may be an act of “identity formation” (27), but as such it can be interpreted as a symptom of “profound self-doubt” (33).
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Saunders, Brian. "Guide to MLA Parenthetical Documentation." Ithaca College Library. January 2007. Web. 22 Oct. 2015.