Voir la notice de l'article provenant de la source Math-Net.Ru
@article{DAN_1993_330_6_a4, author = {P. I. Plotnikov}, title = {Equations with a variable direction of parabolicity and the}, journal = {Doklady Akademii Nauk}, pages = {691--693}, publisher = {mathdoc}, volume = {330}, number = {6}, year = {1993}, language = {ru}, url = {http://geodesic.mathdoc.fr/item/DAN_1993_330_6_a4/} }
P. I. Plotnikov. Equations with a variable direction of parabolicity and the. Doklady Akademii Nauk, Tome 330 (1993) no. 6, pp. 691-693. http://geodesic.mathdoc.fr/item/DAN_1993_330_6_a4/