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
"Gregory VII, Pope, ca. and Emerton, Ephraim",The correspondence of Pope Gregory VII : selected letters from the Registrum,,Norton,1969,"Records of civilization, sources and studies",,,,https://cir.nii.ac.jp/crid/1130282273189321984