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@article{DAN_1971_198_6_a1, author = {Yu. V. Egorov}, title = {On the structure of subelliptic operators}, journal = {Doklady Akademii Nauk}, pages = {1259--1262}, publisher = {mathdoc}, volume = {198}, number = {6}, year = {1971}, language = {ru}, url = {http://geodesic.mathdoc.fr/item/DAN_1971_198_6_a1/} }
Yu. V. Egorov. On the structure of subelliptic operators. Doklady Akademii Nauk, Tome 198 (1971) no. 6, pp. 1259-1262. http://geodesic.mathdoc.fr/item/DAN_1971_198_6_a1/