@inproceedings{i.1994regularity,
title={Regularity of the free boundary in parabolic phase-transition problems},
author={I. Athanasopoulos, L. Caffarelli, and S. Salsa},
url={http://archive.ymsc.tsinghua.edu.cn/pacm_paperurl/20170108203327078749532},
booktitle={Acta Mathematica},
volume={176},
number={2},
pages={245-282},
year={1994},
}
I. Athanasopoulos, L. Caffarelli, and S. Salsa. Regularity of the free boundary in parabolic phase-transition problems. 1994. Vol. 176. In Acta Mathematica. pp.245-282. http://archive.ymsc.tsinghua.edu.cn/pacm_paperurl/20170108203327078749532.