Voir la notice de l'article provenant de la source Math-Net.Ru
@article{DAN_1976_228_4_a1, author = {S. N. Antontsev}, title = {On a problem of {M.\,A.~Lavrent'ev}}, journal = {Doklady Akademii Nauk}, pages = {772--775}, publisher = {mathdoc}, volume = {228}, number = {4}, year = {1976}, language = {ru}, url = {http://geodesic.mathdoc.fr/item/DAN_1976_228_4_a1/} }
S. N. Antontsev. On a problem of M.\,A.~Lavrent'ev. Doklady Akademii Nauk, Tome 228 (1976) no. 4, pp. 772-775. http://geodesic.mathdoc.fr/item/DAN_1976_228_4_a1/