@inproceedings{r.1892zur,
title={Zur Theorie des Krummungsmaasses der Flächen},
author={R. von Lilienthal},
url={http://archive.ymsc.tsinghua.edu.cn/pacm_paperurl/20170108202954726114970},
booktitle={Acta Mathematica},
volume={16},
number={1},
pages={143-152},
year={1892},
}