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
"Petkov, Petko (Petko M.)",The United States and Bulgaria in World War I,,"East European Monographs,Distributed by Columbia University Press",1991,East European monographs,,0880332034,,https://cir.nii.ac.jp/crid/1130282269306255232