@article{DE_1979_15_11_a5,
     author = {G. S. Osipenko},
     title = {Perturbation of dynamical systems near invariant {manifolds.~I}},
     journal = {Differencialʹnye uravneni\^a},
     pages = {1967--1979},
     publisher = {mathdoc},
     volume = {15},
     number = {11},
     year = {1979},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DE_1979_15_11_a5/}
}