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 "Popivanov, Peter R. and Palagachev, Dian K.",The degenerate oblique derivative problem for elliptic and parabolic equations,,Akademie-Verlag,1997,Mathematical research = Mathematische Forschung,,3055017579,,https://cir.nii.ac.jp/crid/1130282271085388928