@article{DAN_1969_187_5_a8,
     author = {Ya. A. Sovin},
     title = {Elliptic boundary value problems for plane regions, with angles and discontinuities occurring on the boundary},
     journal = {Doklady Akademii Nauk},
     pages = {995--997},
     publisher = {mathdoc},
     volume = {187},
     number = {5},
     year = {1969},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DAN_1969_187_5_a8/}
}