APA
Periodical, . (1978). National Geographic Vol 153, No 1-6 ,Jan - June 1978. Washington: National Geographic Society.
Chicago
Periodical, . 1978. National Geographic Vol 153, No 1-6 ,Jan - June 1978. Washington: National Geographic Society.
Harvard
Periodical, . (1978). National Geographic Vol 153, No 1-6 ,Jan - June 1978. Washington: National Geographic Society.
MLA
Periodical, . National Geographic Vol 153, No 1-6 ,Jan - June 1978. Washington: National Geographic Society. 1978.