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 "Elschner, Johannes",Singular ordinary differential operators and pseudodifferential equations,,Akademie-Verlag,1985,Mathematical research = Mathematische Forschung,,,,https://cir.nii.ac.jp/crid/1130000793962472448