অনুরূপ উপাদানগুলি: National Geographic :
- National Geographic : vol. 172, no. 1, July 1987 /
- National Geographic : vol. 172, no. 3, September 1987 /
- National Geographic : vol. 172, no. 4, October 1987 /
- National Geographic : vol. 172, no. 5, November 1987 /
- National Geographic : vol. 172, no. 6, December 1987 /
- National Geographic : vol. 171, no. 2, February 1987 /