@article{DE_1983_19_12_a21,
     author = {A. K. Orlov},
     title = {Periodic solutions of singularly perturbed systems of differential equations},
     journal = {Differencialʹnye uravneni\^a},
     pages = {2176--2177},
     publisher = {mathdoc},
     volume = {19},
     number = {12},
     year = {1983},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DE_1983_19_12_a21/}
}