@inproceedings{j.1894note,
title={Note additionnelle},
author={J. Hadamard},
url={http://archive.ymsc.tsinghua.edu.cn/pacm_paperurl/20170108202958788330004},
booktitle={Acta Mathematica},
volume={18},
number={1},
pages={421-421},
year={1894},
}