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
"Postnikov, M. M. (Mikhail Mikhaĭlovich) and Gelbaum, Bernard R",The variational theory of geodesics,,Dover Publications,2003,Dover phoenix editions,,0486495299,,https://cir.nii.ac.jp/crid/1130282271860110976