MathSciDoc: An Archive for Mathematician ∫

@inproceedings{gerhard1905über,
  title={Über einen geometrischen Calcül (Verknüpfungs-Calcül)},
  author={Gerhard Hessenberg},
  url={http://archive.ymsc.tsinghua.edu.cn/pacm_paperurl/20170108203016413194153},
  booktitle={Acta Mathematica},
  volume={29},
  number={1},
  pages={1-23},
  year={1905},
}