MathSciDoc: An Archive for Mathematician ∫

@inproceedings{arne1949on,
  title={On two problems concerning linear transformations in hilbert space},
  author={Arne Beurling},
  url={http://archive.ymsc.tsinghua.edu.cn/pacm_paperurl/20170108203125716189689},
  booktitle={Acta Mathematica},
  volume={81},
  number={1},
  pages={239-255},
  year={1949},
}