The world coal-mining industry : Vol. 2 / International Labour Office Coal mines and mining. Coal miners. Coal trade. HD4813 .I4 ser. B, no. 31 338 INW At head of title: International labour office ... "Originally prepared and distributed in proof as a 'white' report, intended to serve as a basis for discussion at the Technical tripartite conference on the coal-minimg industry ... in Geneva in May 1938." Geneva : International Labour Office, 1938. 1938. 1938 Text 372 p. : eng Its Studies and reports, Series B (Economic conditions) no. 31 International Labour Office. Studies and reports, Series B (Economic conditions) no. 31.