Oh, the comma—the tiny little pause that holds our lives together. If you’re citing two authors, never put a comma before the “and.” It’s “(Smith and Johnson 42),” not “(Smith, and Johnson 42).” That comma is an intruder. Kick it out.
For three or more authors, the comma goes before “et al.” So it’s “(Garcia et al. 15),” not “(Garcia et al 15).” The comma is like a polite sigh before the gang shows up.
