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 "Ledger, C. K.","Report on the economic situation in the Belgian Congo, dated July, 1924",,H.M.S.O.,1924,Department of Overseas Trade,,,,https://cir.nii.ac.jp/crid/1130000795133696896