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 United States. Bureau of Labor Statistics,"Employee-benefit plans under collective bargaining, mid-1950",,"For sale by the Supt. of Docs., U.S. Govt. Print. Off,U.S. Dept. of Labor, Bureau of Labor Statistics",1951,Bulletin,,,,https://cir.nii.ac.jp/crid/1130282269436383872