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@article{DAN_1957_116_2_a2, author = {M. M. Lavrent'ev}, title = {The maximum principle in the solutions of strongly elliptical second order systems}, journal = {Doklady Akademii Nauk}, pages = {175--176}, publisher = {mathdoc}, volume = {116}, number = {2}, year = {1957}, language = {ru}, url = {http://geodesic.mathdoc.fr/item/DAN_1957_116_2_a2/} }
M. M. Lavrent'ev. The maximum principle in the solutions of strongly elliptical second order systems. Doklady Akademii Nauk, Tome 116 (1957) no. 2, pp. 175-176. http://geodesic.mathdoc.fr/item/DAN_1957_116_2_a2/