著者名,書名,版表示,出版者名,出版年,シリーズ名,番号,ISBN,ISSN,URL
National Research Project on Reemployment Opportunities and Recent Changes in Industrial Techniques (U.S.),Technology and the mineral industries . Mineral technology and output per man studies : grade of ore . Mineral technology and output per man studies : rock drilling . Mechanization trends in metal and nonmetal mining as indicated by sales of underground loading equipment,,"Work Projects Administration, National Research Project",1940,Report,,,,https://cir.nii.ac.jp/crid/1130000795670754048