@article{CRMATH_2002__334_8_661_0,
     author = {Popivanov, Petar and Kutev, Nickolai},
     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},
     url = {http://www.numdam.org/articles/10.1016/S1631-073X(02)02321-X/}
}