@inproceedings{björn1983on,
title={On a differential equation arising in a Hele Shaw flow moving boundary problem},
author={Björn Gustafsson},
url={http://archive.ymsc.tsinghua.edu.cn/pacm_paperurl/20170108203518223833416},
booktitle={Arkiv for Matematik},
volume={22},
number={1},
pages={251-268},
year={1983},
}
Björn Gustafsson. On a differential equation arising in a Hele Shaw flow moving boundary problem. 1983. Vol. 22. In Arkiv for Matematik. pp.251-268. http://archive.ymsc.tsinghua.edu.cn/pacm_paperurl/20170108203518223833416.