@article{DAN_1968_180_3_a6,
     author = {Ya. A. Roitberg},
     title = {Theorems on homeomorphisms which can be realized by elliptic operators},
     journal = {Doklady Akademii Nauk},
     pages = {542--545},
     publisher = {mathdoc},
     volume = {180},
     number = {3},
     year = {1968},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DAN_1968_180_3_a6/}
}