@article{DE_1986_22_3_a7,
     author = {I. G. Petrovskaya},
     title = {On the question of the classification of closed invariant sets of dynamical systems},
     journal = {Differencialʹnye uravneni\^a},
     pages = {426--430},
     publisher = {mathdoc},
     volume = {22},
     number = {3},
     year = {1986},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DE_1986_22_3_a7/}
}