@article{DAN_1991_320_4_a10,
     author = {I. V. Skrypnik},
     title = {A condition for the regularity of a boundary point for a},
     journal = {Doklady Akademii Nauk},
     pages = {821--824},
     publisher = {mathdoc},
     volume = {320},
     number = {4},
     year = {1991},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DAN_1991_320_4_a10/}
}