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
"Singer, Ivan and Georgescu, Radu",Best approximation in normed linear spaces by elements of linear subspaces,,"Pub. House of the Academy of the Socialist Republic of Romania,Springer",1970,Die Grundlehren der mathematischen Wissenschaften,,,,https://cir.nii.ac.jp/crid/1130000796193580800