@article{DAN_1979_246_4_a11,
     author = {V. A. Kondrat'ev and S. D. \`Eidel'man},
     title = {On conditions on the boundary surface in the theory of elliptic boundary value problems},
     journal = {Doklady Akademii Nauk},
     pages = {812--815},
     year = {1979},
     volume = {246},
     number = {4},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DAN_1979_246_4_a11/}
}