The writer is quoting from page 543 of the following book:

Myers, D. G. (2002). Exploring psychology (5th ed.). Boston, MA: Worth.

As one discussion of Milgram’s obedience studies points out, “great evils sometimes grow out of people’s compliance with lesser evils” (Myers, 2002, p. 543).

As one discussion of Milgram’s obedience studies points out, “great evils sometimes grow out of people’s compliance with lesser evils” (Myers, p. 543).

The year must be included in the parentheses in an APA in-text citation.