@article{GDZPPN002213540,
title = {Existence and geometric properties of solutions of a free boundary problem in potential theory.},
journal = {Journal f\"ur die reine und angewandte Mathematik},
volume = {468},
year = {1995},
pages = {137-180},
zbl = {0846.31005},
url = {http://dml.mathdoc.fr/item/GDZPPN002213540}
}
Gustafsson, Björn; Shahgholian, Henrik. Existence and geometric properties of solutions of a free boundary problem in potential theory.. Journal für die reine und angewandte Mathematik, Tome 468 (1995) pp. 137-180. http://gdmltest.u-ga.fr/item/GDZPPN002213540/