1. ANON. (1971) Management of nutrients in agricultural land for improved water quality. Environ. Prot. Ag. Rep. 13020 DPB 08/71, p. 151.
2. ANON. (1972) Effects of intensive fertilizer use on the human environment. Soils Bull. FAO 16, p. 360.
3. ANON. (1973) Impact of fertilizers and agricultural waste products on the quality of waters. OECD Rep., Paris, September 1973, p. 72.
4. ANON. (1974) The pollution of waters by agriculture and forestry. UN Econ. Social Council, Econ. Comm. Eur., Committee Water Probl., Water Sem. 1/2, 13 jan. 1974, p. 124.
5. Nitrate in unsaturated zone of an alluvial soil in relation to fertilizer nitrogen rate and irrigation level;ADRIANO;J. environ. Qual.,1972