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
"Toft, Bjarne",On separating sets of edges in contraction-critical graphs,,"Aarhus universitet, Matematisk institut",1971,Preprint series,,,,https://cir.nii.ac.jp/crid/1130000794626434688