On the Dirichlet problem for quasilinear elliptic second order equations with triple degeneracy and singularity in a domain with a boundary conical point. Borsuk, Michail; Portnyagin, Dmitriy — 1999 Electronic Journal of Differential Equations (EJDE) [electronic only]
Barriers on cones for degenerate quasilinear elliptic operators. Borsuk, Michail; Portnyagin, Dmitriy — 1998 Electronic Journal of Differential Equations (EJDE) [electronic only]