@inproceedings{yu-lin2009perturbation,
title={Perturbation theorems for Hele-Shaw flows and their applications},
author={Yu-Lin Lin},
url={http://archive.ymsc.tsinghua.edu.cn/pacm_paperurl/20170108203630908039007},
booktitle={Arkiv for Matematik},
volume={49},
number={2},
pages={357-382},
year={2009},
}
Yu-Lin Lin. Perturbation theorems for Hele-Shaw flows and their applications. 2009. Vol. 49. In Arkiv for Matematik. pp.357-382. http://archive.ymsc.tsinghua.edu.cn/pacm_paperurl/20170108203630908039007.