@article{10_1090_S0894_0347_04_00466_7,
     author = {Caffarelli, Luis and Petrosyan, Arshak and Shahgholian, Henrik},
     title = {Regularity of a free boundary in parabolic potential theory},
     journal = {Journal of the American Mathematical Society},
     pages = {827--869},
     publisher = {mathdoc},
     volume = {17},
     number = {4},
     year = {2004},
     doi = {10.1090/S0894-0347-04-00466-7},
     url = {http://geodesic.mathdoc.fr/articles/10.1090/S0894-0347-04-00466-7/}
}