Liknande verk: National Geographic :
- National Geographic : vol. 144, no. 2, August 1973 /
- National Geographic : vol. 144, no. 3, September 1973 /
- National Geographic : vol. 144, no. 4, October 1973 /
- National Geographic : vol. 144, no. 5, November 1973 /
- National Geographic : vol. 144, no. 6, December 1973 /
- National Geographic : vol. 143, no. 1, January 1973 /