Cita APA (7a ed.)

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

Cita Chicago Style (17a ed.)

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

Cita MLA (9a ed.)

National Geographic Society (U.S.) y Carol Bittig Lutyk. Our World's Heritage. National Geographic Society, 1987.