If your source has two authors, you just link them with the word “and.” No commas, no drama. In your text, you write (Smith and Jones 42), and in your Works Cited, it becomes: Smith, John, and Jane Jones. Title of Book. Publisher, Year.
That’s it. Really. No need to weep into your keyboard. It’s the same logic as introducing your two best friends at a party: “This is Sarah, and this is Bob.” See? Easy.
Don’t overthink the comma after the first author’s name. It’s always there: Last name, First name. Then “and,” then the second author’s First name Last name. Your professor will expect this, and they’ll be happy.
