If more than one work by an author is cited, include shortened titles for the works to distinguish them from each other.
Example if the author’s name is mentioned:
Obama has argued that the invasion was a bad idea (“Too Soon” 42), though he has acknowledged elsewhere that it led to much good (“A Stronger Country” 13).
Example if the author’s name and title are mentioned:
In “Too Soon,” Obama argued that the invasion was a bad idea (42).
Example if the author’s name is not mentioned in the sentence:
Photography, because it is both science and art, seems to be “a bridge discipline” (Barthes, “Of Loss and Cameras” 45).
Notice that when all three elements are used within the parenthetical citation, there is a comma added after the author’s name.