MathSciDoc: An Archive for Mathematician ∫

@inproceedings{jakob1942abbildungsklassen,
  title={Abbildungsklassen Endlicher Ordnung},
  author={Jakob Nielsen},
  url={http://archive.ymsc.tsinghua.edu.cn/pacm_paperurl/20170108203118646351636},
  booktitle={Acta Mathematica},
  volume={75},
  number={1},
  pages={23-115},
  year={1942},
}