@article{DE_2006_42_11_a6,
     author = {N. A. Magnitskii and S. V. Sidorov},
     title = {Dynamical chaos in two-dimensional nonlinear nonautonomous systems of ordinary differential equations},
     journal = {Differencialʹnye uravneni\^a},
     pages = {1507--1514},
     publisher = {mathdoc},
     volume = {42},
     number = {11},
     year = {2006},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DE_2006_42_11_a6/}
}