@article{SM_1975_27_4_a0,
     author = {A. I. Achil'diev},
     title = {A~mixed boundary value problem for some degenerate elliptic equations},
     journal = {Sbornik. Mathematics},
     pages = {447--462},
     publisher = {mathdoc},
     volume = {27},
     number = {4},
     year = {1975},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/SM_1975_27_4_a0/}
}