@article{DE_1984_20_6_a2,
     author = {A. S. Gurtovnik and Yu. I. Neimark},
     title = {Global investigation of a nonautonomously perturbed nonlinear oscillator},
     journal = {Differencialʹnye uravneni\^a},
     pages = {941--952},
     publisher = {mathdoc},
     volume = {20},
     number = {6},
     year = {1984},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DE_1984_20_6_a2/}
}