@article{CRMATH_2002__334_8_661_0,
     author = {Petar Popivanov and Nickolai Kutev},
     title = {Viscosity solutions to the degenerate oblique derivative problem for fully nonlinear elliptic equations},
     journal = {Comptes Rendus. Math\'ematique},
     pages = {661--666},
     publisher = {Elsevier},
     volume = {334},
     number = {8},
     year = {2002},
     doi = {10.1016/S1631-073X(02)02321-X},
     language = {en},
}