Liknande verk: National Geographic :
- National Geographic : vol. 147, no. 2, February 1975 /
- National Geographic : vol. 147, no. 3, March 1975 /
- National Geographic : vol. 147, no. 4, April 1975 /
- National Geographic : vol. 147, no. 5, May 1975 /
- National Geographic : vol. 147, no. 6, June 1975 /
- National Geographic : vol. 148, no. 1, July 1975 /