IUCN -Gland, CH, International Union for Conservation of Nature, Gland, C. H. W. W. F. -, and Nairobi, K. E. U. N. E. P. -,
Caring for the earth : a strategy for sustainable living. Gland, Switzerland: IUCN - International Union for Conservation of Nature, 1991, p. iv, 228 p.
C. Wheal,
“Freshwater pollution”, vol. no. 6. UNEP, United Nations Environment Programme, Nairobi, Kenya, p. 36 p.: tab., fig., map, photogr., 1991.