@article{DE_1994_30_3_a0,
     author = {A. K. Demenchuk},
     title = {Quasiperiodic solutions of differential systems with a single-frequency nonlinearity in the case of several pairs of purely imaginary eigenvalues},
     journal = {Differencialʹnye uravneni\^a},
     pages = {371--376},
     publisher = {mathdoc},
     volume = {30},
     number = {3},
     year = {1994},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DE_1994_30_3_a0/}
}