Biblio

N. L. W. W. F. - Zeist, “Living waters : conserving the source of life : thirsty crops : our food and clothes: eating up nature and wearing out he environment?”. WWF International, Zeist, The Netherlands, p. 18 p. : boxes, photogr., 2006.

N. L. W. W. F. - Zeist, “Milestones in water conservation : global freshwater programme”. WWF International, Zeist, The Netherlands, p. 13 p. : fig., photogr., 2006.