333.91
U58L
               Long-term planning of water management proceedings of the seminar on long-term planning of water management, Zlatni Piasatzi (Bulgaria)17-22 May 1976 - New York : United Nations, 1976.
               3v. V.p - ECE/Water/15 .
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                Subjects: Water quality-Management; Water resources development; Water conservation; Water resources development-Environmental aspects.