00562nam a2200109Ia 4500 180412s9999||||xx |||||||||||||| ||und|| Ahmadu Bello University Library - Zaria HENDERSON, Kay Pollution; sources of information. Proceedings of a one day conference held at the Library Association London on 27th October 1971. Kay Henderson Library Association; London. 1972 101p. Impurity, pollution, nuisances, offensive trades. General purification of the air. Metal and their inorganic compounds. Non-metallic elements. 1819 1819