APA (7th ed.) Citation

National Geographic Society (U.S.), National Geographic Book Service, & Lutyk, C. B. (1987). Our world's heritage. National Geographic Society.

Chicago Style (17th ed.) Citation

National Geographic Society (U.S.), National Geographic Book Service, and Carol Bittig Lutyk. Our World's Heritage. Washington, D.C.: National Geographic Society, 1987.

MLA (8th ed.) Citation

National Geographic Society (U.S.), et al. Our World's Heritage. National Geographic Society, 1987.