@article{SM_1981_40_3_a2,
     author = {V. V. Katrakhov},
     title = {General boundary value problems for a~class of singular and degenerate elliptic equations},
     journal = {Sbornik. Mathematics},
     pages = {325--347},
     publisher = {mathdoc},
     volume = {40},
     number = {3},
     year = {1981},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/SM_1981_40_3_a2/}
}