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@article{MZM_1991_49_2_a19, author = {Nguyen Minh Tri}, title = {Global hypoellipticity property of a differential operator}, journal = {Matemati\v{c}eskie zametki}, pages = {147--150}, publisher = {mathdoc}, volume = {49}, number = {2}, year = {1991}, language = {ru}, url = {http://geodesic.mathdoc.fr/item/MZM_1991_49_2_a19/} }
Nguyen Minh Tri. Global hypoellipticity property of a differential operator. Matematičeskie zametki, Tome 49 (1991) no. 2, pp. 147-150. http://geodesic.mathdoc.fr/item/MZM_1991_49_2_a19/