@article{DAN_1973_210_1_a7,
     author = {Ya. A. Roitberg},
     title = {Isomorphism theorems and elliptic problems with potentials},
     journal = {Doklady Akademii Nauk},
     pages = {33--36},
     publisher = {mathdoc},
     volume = {210},
     number = {1},
     year = {1973},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DAN_1973_210_1_a7/}
}