@article{SM_1970_11_4_a2,
     author = {V. I. Feigin},
     title = {On~the smoothness of the solutions of boundary value problems for parabolic and degenerate elliptic equations},
     journal = {Sbornik. Mathematics},
     pages = {507--528},
     publisher = {mathdoc},
     volume = {11},
     number = {4},
     year = {1970},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/SM_1970_11_4_a2/}
}