@article{DE_1980_16_4_a3,
     author = {G. S. Osipenko},
     title = {Perturbation of dynamical systems near invariant {manifolds.~II}},
     journal = {Differencialʹnye uravneni\^a},
     pages = {620--628},
     publisher = {mathdoc},
     volume = {16},
     number = {4},
     year = {1980},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DE_1980_16_4_a3/}
}