Viscosity solutions and regularity of the free boundary for the limit of an elliptic two phase singular perturbation problem Claudia Lederman; Noemi Wolanski — 1998 Annali della Scuola Normale Superiore di Pisa - Classe di Scienze
A mixed semilinear parabolic problem from combustion theory. Lederman, Claudia; Vazquez, Juan Luis; Wolanski, Noemi — 2001 Electronic Journal of Differential Equations (EJDE) [electronic only]