APA (7e ed.) Bronvermelding
Garret, W. E. National Geographic: Vol. 177, no. 1, January 1990. National Geographic Society.
Chicago (17e ed.) Bronvermelding
Garret, Wilbur E. National Geographic: Vol. 177, No. 1, January 1990. Washington, EUA: National Geographic Society.
MLA (9e ed.) Bronvermelding
Garret, Wilbur E. National Geographic: Vol. 177, No. 1, January 1990. National Geographic Society.
Let op: Deze citaties zijn niet altijd 100% accuraat.