Voir la notice de l'article provenant de la source Math-Net.Ru
@article{DAN_1980_254_6_a13, author = {Ya. A. Roitberg and Z. G. Sheftel}, title = {On general elliptic problems with strong degeneration}, journal = {Doklady Akademii Nauk}, pages = {1336--1342}, publisher = {mathdoc}, volume = {254}, number = {6}, year = {1980}, language = {ru}, url = {http://geodesic.mathdoc.fr/item/DAN_1980_254_6_a13/} }
Ya. A. Roitberg; Z. G. Sheftel. On general elliptic problems with strong degeneration. Doklady Akademii Nauk, Tome 254 (1980) no. 6, pp. 1336-1342. http://geodesic.mathdoc.fr/item/DAN_1980_254_6_a13/