@article{DAN_1962_144_2_a3,
     author = {K. V. Zadiraka},
     title = {Investigation of singularly perturbed systems in the neighborhood of a family of closed orbits},
     journal = {Doklady Akademii Nauk},
     pages = {264--267},
     publisher = {mathdoc},
     volume = {144},
     number = {2},
     year = {1962},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DAN_1962_144_2_a3/}
}