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@article{DE_1978_14_11_a26, author = {L. F. Yanchuk}, title = {The asymptotic equivalence of {Pfaffian} systems}, journal = {Differencialʹnye uravneni\^a}, pages = {2099--2103}, publisher = {mathdoc}, volume = {14}, number = {11}, year = {1978}, language = {ru}, url = {http://geodesic.mathdoc.fr/item/DE_1978_14_11_a26/} }
L. F. Yanchuk. The asymptotic equivalence of Pfaffian systems. Differencialʹnye uravneniâ, Tome 14 (1978) no. 11, pp. 2099-2103. http://geodesic.mathdoc.fr/item/DE_1978_14_11_a26/