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 H.P. Drewry (Shipping Consultants) Limited. Research Division,Trends in tanker operations and economics,,Drewry,1979,An Economic study,,,,https://cir.nii.ac.jp/crid/1130282268828898176