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@article{DE_1980_16_6_a0, author = {\`E. I. Grudo}, title = {A differential system with two purely imaginary roots of a characteristic equation}, journal = {Differencialʹnye uravneni\^a}, pages = {963--979}, publisher = {mathdoc}, volume = {16}, number = {6}, year = {1980}, language = {ru}, url = {http://geodesic.mathdoc.fr/item/DE_1980_16_6_a0/} }
È. I. Grudo. A differential system with two purely imaginary roots of a characteristic equation. Differencialʹnye uravneniâ, Tome 16 (1980) no. 6, pp. 963-979. http://geodesic.mathdoc.fr/item/DE_1980_16_6_a0/