@article{RM_1967_22_5_a10,
     author = {Ya. A. Roitberg and Z. G. Sheftel},
     title = {Green's formula and a~theorem on homeomorphisms for elliptic systems},
     journal = {Trudy Matematicheskogo Instituta imeni V.A. Steklova},
     publisher = {mathdoc},
     volume = {22},
     number = {5},
     year = {1967},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/RM_1967_22_5_a10/}
}