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@article{DE_1986_22_11_a16, author = {A. Yanushauskas}, title = {On non-strongly-elliptic systems of second-order partial differential equations}, journal = {Differencialʹnye uravneni\^a}, pages = {1984--1990}, publisher = {mathdoc}, volume = {22}, number = {11}, year = {1986}, language = {ru}, url = {http://geodesic.mathdoc.fr/item/DE_1986_22_11_a16/} }
A. Yanushauskas. On non-strongly-elliptic systems of second-order partial differential equations. Differencialʹnye uravneniâ, Tome 22 (1986) no. 11, pp. 1984-1990. http://geodesic.mathdoc.fr/item/DE_1986_22_11_a16/