@inproceedings{alfred1901erklärung,
title={Erklärung},
author={Alfred Pringsheim},
url={http://archive.ymsc.tsinghua.edu.cn/pacm_paperurl/20170108203007028421073},
booktitle={Acta Mathematica},
volume={24},
number={1},
pages={245-245},
year={1901},
}