@article{DAN_1985_285_2_a8,
     author = {B. L. Fain},
     title = {Extension of functions from {Sobolev} spaces for irregular domains preserving the index of smoothness},
     journal = {Doklady Akademii Nauk},
     pages = {296--301},
     publisher = {mathdoc},
     volume = {285},
     number = {2},
     year = {1985},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DAN_1985_285_2_a8/}
}