Cita APA (7th ed.)
Grosvenor, M. B. National Geographic: Vol. 139, no. 1, January 1971. National Geographic Society.
Cita Chicago (17th ed.)
Grosvenor, Melville Bell. National Geographic: Vol. 139, No. 1, January 1971. Washington, EUA: National Geographic Society.
Cita MLA (9th ed.)
Grosvenor, Melville Bell. National Geographic: Vol. 139, No. 1, January 1971. National Geographic Society.
Atenció: Aquestes cites poden no estar 100% correctes.