World directory of national parks and other protected areas
1977
IUCN
Establishment and management of protected areas in the Gobi region, Mongolian People's Republic : report of an international mission, May-June 1976
1976
Child, Graham |
Hunkeler, P. |
Proceedings : International Conference on the Conservation of Wetlands and Waterfowl, Ramsar, Iran, 30 January - 3 February 1971
1972
Carp, Erik |
Project aqua : a source book of inland waters proposed for conservation
1971
Luther, H. |
Rzóska, J. |
Worthington, E. B. |
Interférences de l'homme sur la nature : les équilibres biologiques. Appel aux jeunes gens
1968
Pavan, Mario |