Voir la notice de l'article provenant de la source Math-Net.Ru
@article{TRSPY_1972_117_a14, author = {S. V. Uspenskii}, title = {The representation of functions defined by a certain class of hypoelliptic operators}, journal = {Informatics and Automation}, pages = {292--299}, publisher = {mathdoc}, volume = {117}, year = {1972}, language = {ru}, url = {http://geodesic.mathdoc.fr/item/TRSPY_1972_117_a14/} }
S. V. Uspenskii. The representation of functions defined by a certain class of hypoelliptic operators. Informatics and Automation, Investigations in the theory of differentiable functions of many variables and its applications. Part IV, Tome 117 (1972), pp. 292-299. http://geodesic.mathdoc.fr/item/TRSPY_1972_117_a14/