@inproceedings{michael1991a,
title={A simplified proof for a moving boundary problem for Hele-Shaw flows in the plane},
author={Michael Reissig, and Lothar v. Wolfersdorf},
url={http://archive.ymsc.tsinghua.edu.cn/pacm_paperurl/20170108203539793218596},
booktitle={Arkiv for Matematik},
volume={31},
number={1},
pages={101-116},
year={1991},
}
Michael Reissig, and Lothar v. Wolfersdorf. A simplified proof for a moving boundary problem for Hele-Shaw flows in the plane. 1991. Vol. 31. In Arkiv for Matematik. pp.101-116. http://archive.ymsc.tsinghua.edu.cn/pacm_paperurl/20170108203539793218596.