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@article{DAN_1978_240_4_a7, author = {R. S. Saks}, title = {Weakly elliptic systems of pseudodifferential equations on a manifold without boundary}, journal = {Doklady Akademii Nauk}, pages = {786--789}, publisher = {mathdoc}, volume = {240}, number = {4}, year = {1978}, language = {ru}, url = {http://geodesic.mathdoc.fr/item/DAN_1978_240_4_a7/} }
R. S. Saks. Weakly elliptic systems of pseudodifferential equations on a manifold without boundary. Doklady Akademii Nauk, Tome 240 (1978) no. 4, pp. 786-789. http://geodesic.mathdoc.fr/item/DAN_1978_240_4_a7/