Columbia subject headings:
Harvard subject headings:
Conservation of natural resources--Bibliography--Catalogs.
United Nations--Catalogs.
Water quality--Bibliography--Catalogs.
Water resources development--Bibliography--Catalogs.
Water--Law and legislation--Bibliography--Catalogs.
Water-supply--Bibliography--Catalogs.
Princeton subject headings:
Conservation of natural resources--Bibliography--Catalogs.
United Nations--Catalogs.
Water quality--Bibliography--Catalogs.
Water resources development--Bibliography--Catalogs.
Water-supply--Bibliography--Catalogs.