@inproceedings{gaston1920extension,
title={Extension nouvelle d'un lemme de Schwarz},
author={Gaston Julia},
url={http://archive.ymsc.tsinghua.edu.cn/pacm_paperurl/20170108203036143710307},
booktitle={Acta Mathematica},
volume={42},
number={1},
pages={349-355},
year={1920},
}