@article{DAN_1991_317_1_a6,
     author = {Yu. A. Mitropol'skii and I. Kurbanov},
     title = {Solvability of the boundary value problems of},
     journal = {Doklady Akademii Nauk},
     pages = {35--39},
     publisher = {mathdoc},
     volume = {317},
     number = {1},
     year = {1991},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DAN_1991_317_1_a6/}
}