APA (7th ed.) Citation

Anthony, P., & Margroff, R. E. (1990). Orc's opal. Tor Books.

Chicago Style (17th ed.) Citation

Anthony, Piers, and Robert E. Margroff. Orc's Opal. New York: Tor Books, 1990.

MLA (9th ed.) Citation

Anthony, Piers, and Robert E. Margroff. Orc's Opal. Tor Books, 1990.