APA (7th ed.) Citation

Bishop, M., Horizon magazine, & Kotker, N. (1966). Horizon book of the middle ages. American Heritage Publishing Company.

Chicago Style (17th ed.) Citation

Bishop, Morris, Horizon magazine, and Norman Kotker. Horizon Book of the Middle Ages. New York: American Heritage Publishing Company, 1966.

MLA (9th ed.) Citation

Bishop, Morris, et al. Horizon Book of the Middle Ages. American Heritage Publishing Company, 1966.