Gaya APA
National Geographic Vol. 157, No.1 January 1980. (1980).
Washington, D.C.:
National Geographic Society.
Gaya Chicago
National Geographic Vol. 157, No.1 January 1980.
.
Washington, D.C.:
National Geographic Society,
1980.
Text.
Gaya MLA
National Geographic Vol. 157, No.1 January 1980.
.
Washington, D.C.:
National Geographic Society,
1980.
Text.
Gaya Turabian
National Geographic Vol. 157, No.1 January 1980.
Washington, D.C.:
National Geographic Society,
1980.
Print.