APA Style
National Geographic: Vol.191-192, No.1-6: January 1997-December 1997. ().
Washington, D.C.:
National Geographic Society.
Chicago Style
National Geographic: Vol.191-192, No.1-6: January 1997-December 1997.
.
Washington, D.C.:
National Geographic Society,
.
Text.
MLA Style
National Geographic: Vol.191-192, No.1-6: January 1997-December 1997.
.
Washington, D.C.:
National Geographic Society,
.
Text.
Turabian Style
National Geographic: Vol.191-192, No.1-6: January 1997-December 1997.
Washington, D.C.:
National Geographic Society,
.
Print.