@article{DAN_1963_148_4_a1,
     author = {Yu. M. Berezanskii and S. G. Krein and Ya. A. Roitberg},
     title = {A theorem on homeomorphisms and local increase of smoothness up to the boundary for solutions of elliptic equations},
     journal = {Doklady Akademii Nauk},
     pages = {745--748},
     publisher = {mathdoc},
     volume = {148},
     number = {4},
     year = {1963},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DAN_1963_148_4_a1/}
}