APA (7th ed.) Citation

Asimov, I. (1990). Puzzles of the black widowers (1. ed.). Doubleday.

Chicago Style (17th ed.) Citation

Asimov, Isaac. Puzzles of the Black Widowers. 1. ed. New York u.a: Doubleday, 1990.

MLA (9th ed.) Citation

Asimov, Isaac. Puzzles of the Black Widowers. 1. ed. Doubleday, 1990.