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@article{DAN_1985_281_3_a0, author = {V. A. Ginzburg}, title = {A theorem on the index of differential systems and the geometry of}, journal = {Doklady Akademii Nauk}, pages = {521--525}, publisher = {mathdoc}, volume = {281}, number = {3}, year = {1985}, language = {ru}, url = {http://geodesic.mathdoc.fr/item/DAN_1985_281_3_a0/} }
V. A. Ginzburg. A theorem on the index of differential systems and the geometry of. Doklady Akademii Nauk, Tome 281 (1985) no. 3, pp. 521-525. http://geodesic.mathdoc.fr/item/DAN_1985_281_3_a0/