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@article{DE_1999_35_7_a4, author = {E. N. Krupchik}, title = {Lower characteristic exponents of nontrivial solutions of {Pfaffian} systems}, journal = {Differencialʹnye uravneni\^a}, pages = {899--908}, publisher = {mathdoc}, volume = {35}, number = {7}, year = {1999}, language = {ru}, url = {http://geodesic.mathdoc.fr/item/DE_1999_35_7_a4/} }
E. N. Krupchik. Lower characteristic exponents of nontrivial solutions of Pfaffian systems. Differencialʹnye uravneniâ, Tome 35 (1999) no. 7, pp. 899-908. http://geodesic.mathdoc.fr/item/DE_1999_35_7_a4/