Voir la notice de l'article provenant de la source Math-Net.Ru
@article{DAN_1964_156_6_a2, author = {L. R. Volevich}, title = {On hypo-elliptic systems with variable coefficients}, journal = {Doklady Akademii Nauk}, pages = {1262--1265}, publisher = {mathdoc}, volume = {156}, number = {6}, year = {1964}, language = {ru}, url = {http://geodesic.mathdoc.fr/item/DAN_1964_156_6_a2/} }
L. R. Volevich. On hypo-elliptic systems with variable coefficients. Doklady Akademii Nauk, Tome 156 (1964) no. 6, pp. 1262-1265. http://geodesic.mathdoc.fr/item/DAN_1964_156_6_a2/