Ecology and coal resource development : based on the International Congress for Energy and the Ecosystem, held at the University of North Dakota, Grand Forks, North Dakota, 12-16 June, 1978, vol. 1 / edited by Mohan K. Wali. International Congress for Energy and the Ecosystem (1978 : University of North Dakota) Wali, Mohan K. Coal Congresses. Coal mines and mining Congresses. Energy policy Congresses. Environmental protection Congresses. TN799.9 .I63 1978 333.82 WAE Includes bibliographical references and index. New York : Pergamon, c1979. c1979. 1979 Text 2v : eng