@article{DE_1990_26_8_a8,
     author = {S. D. Furta},
     title = {Asymptotic solutions of systems of differential equations in the case of purely imaginary eigenvalues},
     journal = {Differencialʹnye uravneni\^a},
     pages = {1348--1351},
     year = {1990},
     volume = {26},
     number = {8},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DE_1990_26_8_a8/}
}