@article{JRAM_1986__368_152837,
     author = {H.W. Alt and D. Phillips},
     title = {A free boundary problem for semilinear elliptic equations.},
     journal = {Journal f\"ur die reine und angewandte Mathematik},
     pages = {63--107},
     publisher = {mathdoc},
     volume = {368},
     year = {1986},
     zbl = {0598.35132},
     url = {http://geodesic.mathdoc.fr/item/JRAM_1986__368_152837/}
}