APA (7th ed.) Citation

Keith, J. A., & Williamson, J. (1988). The Legion at war (Ace ed.). Berkley.

Chicago Style (17th ed.) Citation

Keith, J. Andrew, and Jack Williamson. The Legion at War. Ace ed. New York: Berkley, 1988.

MLA (9th ed.) Citation

Keith, J. Andrew, and Jack Williamson. The Legion at War. Ace ed. Berkley, 1988.