@article{DAN_1978_239_3_a9,
     author = {I. V. Skrypnik},
     title = {On a topological characteristic of general nonlinear elliptic operators},
     journal = {Doklady Akademii Nauk},
     pages = {538--541},
     publisher = {mathdoc},
     volume = {239},
     number = {3},
     year = {1978},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DAN_1978_239_3_a9/}
}