NL Troll - 543 1967 - [ca. 1971]
Unesco / Natural Resources Research Division
Enth.: - ... Session (hekt., Nr. 2.1967); Final Report, ... Session (hekt. u.a., Nr. 2.1967); Recommendations, Intergovernmental Conference of Experts on the scientific basis for rational use and conservation of the resources of the biosphere (hekt., 1968); Natural science and their application to development (Ausz., Dr., [ca. 1969, 1971])
208 Bl., 1 H.