Voir la notice de l'article provenant de la source Math-Net.Ru
@article{DAN_1962_146_6_a7, author = {Ya. A. Roitberg and Z. G. Sheftel}, title = {On equations of elliptic type with discontinuous coefficients}, journal = {Doklady Akademii Nauk}, pages = {1275--1278}, publisher = {mathdoc}, volume = {146}, number = {6}, year = {1962}, language = {ru}, url = {http://geodesic.mathdoc.fr/item/DAN_1962_146_6_a7/} }
Ya. A. Roitberg; Z. G. Sheftel. On equations of elliptic type with discontinuous coefficients. Doklady Akademii Nauk, Tome 146 (1962) no. 6, pp. 1275-1278. http://geodesic.mathdoc.fr/item/DAN_1962_146_6_a7/