MathSciDoc: An Archive for Mathematician ∫

@inproceedings{lars1958definitions,
  title={Definitions of maximal differential operators},
  author={Lars Hörmander},
  url={http://archive.ymsc.tsinghua.edu.cn/pacm_paperurl/20170108203423152005947},
  booktitle={Arkiv for Matematik},
  volume={3},
  number={6},
  pages={501-504},
  year={1958},
}