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, Kiril","The voices of medieval Bulgaria, seventh-fifteenth century : the records of a bygone culture",,Brill,2008,"East Central and Eastern Europe in the Middle Ages, 450-1450",,9789004168312,,https://cir.nii.ac.jp/crid/1130000795232134912