@inproceedings{arthur1903a,
title={A generalisation of a theorem of M. Picard with regard to integrals of the first kind of total differentials},
author={Arthur Berry},
url={http://archive.ymsc.tsinghua.edu.cn/pacm_paperurl/20170108203012731760122},
booktitle={Acta Mathematica},
volume={27},
number={1},
pages={157-162},
year={1903},
}
Arthur Berry. A generalisation of a theorem of M. Picard with regard to integrals of the first kind of total differentials. 1903. Vol. 27. In Acta Mathematica. pp.157-162. http://archive.ymsc.tsinghua.edu.cn/pacm_paperurl/20170108203012731760122.