@inproceedings{chr1887kalender-formeln,
title={Kalender-Formeln},
author={Chr Zeller},
url={http://archive.ymsc.tsinghua.edu.cn/pacm_paperurl/20170108202945766637889},
booktitle={Acta Mathematica},
volume={9},
number={1},
pages={131-136},
year={1887},
}