@article{SM_1996_187_11_a4,
     author = {B. Yu. Sternin and V. E. Shatalov},
     title = {Relative elliptic theory and {the~Sobolev} problem},
     journal = {Sbornik. Mathematics},
     pages = {1691--1720},
     publisher = {mathdoc},
     volume = {187},
     number = {11},
     year = {1996},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/SM_1996_187_11_a4/}
}