@article{SM_1968_6_3_a0,
     author = {S. N. Kruzhkov},
     title = {Boundary value problems for degenerate second order elliptic equations},
     journal = {Sbornik. Mathematics},
     pages = {275--307},
     publisher = {mathdoc},
     volume = {6},
     number = {3},
     year = {1968},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/SM_1968_6_3_a0/}
}