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 "Groen, Peter Paul Nicolaas de",Singularly perturbed differential operators of second order,,Mathematisch Centrum,1976,Mathematical Centre tracts,,9061961203,,https://cir.nii.ac.jp/crid/1130282271777934720