著者名,論文名,雑誌名,ISSN,出版者名,出版日付,巻,号,ページ,URL,URL(DOI)
Arne Beurling,On two problems concerning linear transformations in hilbert space,Acta Mathematica,0001-5962,International Press of Boston,1949,81,0,239-255,https://cir.nii.ac.jp/crid/1361137044656536704,https://doi.org/10.1007/bf02395019