APA (7th ed.) Citation

Howard, R. E., De Camp, L. S., & Carter, L. (1968). Conan the wanderer. Prestige Books.

Chicago Style (17th ed.) Citation

Howard, Robert E., L. Sprague De Camp, and Lin Carter. Conan the Wanderer. [New York?]: Prestige Books, 1968.

MLA (9th ed.) Citation

Howard, Robert E., et al. Conan the Wanderer. Prestige Books, 1968.