@article{DE_1975_11_8_a6,
     author = {A. M. Samoilenko and I. V. Polesya},
     title = {Occurrence of invariant sets in the neighborhood of the equilibrium position},
     journal = {Differencialʹnye uravneni\^a},
     pages = {1409--1415},
     publisher = {mathdoc},
     volume = {11},
     number = {8},
     year = {1975},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DE_1975_11_8_a6/}
}