Cita APA (7th ed.)
Garret, W. E. National Geographic: Vol. 172, no. 1, July 1987. National Geographic Society.
Cita Chicago (17th ed.)
Garret, Wilbur E. National Geographic: Vol. 172, No. 1, July 1987. Washington, EUA: National Geographic Society.
Cita MLA (9th ed.)
Garret, Wilbur E. National Geographic: Vol. 172, No. 1, July 1987. National Geographic Society.
Atenció: Aquestes cites poden no estar 100% correctes.