@article{DE_1981_17_4_a8,
     author = {I. V. Polesya},
     title = {Invariant sets of autonomous differential systems},
     journal = {Differencialʹnye uravneni\^a},
     pages = {643--650},
     publisher = {mathdoc},
     volume = {17},
     number = {4},
     year = {1981},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DE_1981_17_4_a8/}
}