Ижил төстэй зүйлс: National Geographic :
- National Geographic : vol. 134, no. 1, July 1968 /
- National Geographic : vol. 134, no. 2, August 1968 /
- National Geographic : vol. 134, no. 3, September 1968 /
- National Geographic : vol. 134, no. 4, October 1968 /
- National Geographic : vol. 134, no. 5, November 1968 /
- National Geographic : vol. 133, no. 6, June 1968 /