APA (7th ed.) Zitazioa
Garret, W. E. National Geographic: Vol. 177, no. 1, January 1990. National Geographic Society.
Chicago Style (17th ed.) Zitazioa
Garret, Wilbur E. National Geographic: Vol. 177, No. 1, January 1990. Washington, EUA: National Geographic Society.
MLA (9th ed.) Zitazioa
Garret, Wilbur E. National Geographic: Vol. 177, No. 1, January 1990. National Geographic Society.
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