Documenti analoghi: National Geographic :
- National Geographic : vol. 149, no. 2, February 1976 /
- National Geographic : vol. 149, no. 3, March 1976 /
- National Geographic : vol. 149, no. 4, April 1976 /
- National Geographic : vol. 149, no. 6, June 1976 /
- National Geographic : vol. 149, no. 1, January 1976 /
- National Geographic : vol. 150, no. 5, November 1976 /