APA Style
National Geographic: Vol.193-194, No.1-6: January 1998-December 1998. ().
Washington, D.C.:
National Geographic Society.
Chicago Style
National Geographic: Vol.193-194, No.1-6: January 1998-December 1998.
.
Washington, D.C.:
National Geographic Society,
.
Text.
MLA Style
National Geographic: Vol.193-194, No.1-6: January 1998-December 1998.
.
Washington, D.C.:
National Geographic Society,
.
Text.
Turabian Style
National Geographic: Vol.193-194, No.1-6: January 1998-December 1998.
Washington, D.C.:
National Geographic Society,
.
Print.