@article{DE_1966_2_6_a5,
     author = {M. T. Terekhin},
     title = {Periodic solutions of a certain nonautonomous system of differential equations},
     journal = {Differencialʹnye uravneni\^a},
     pages = {778--782},
     publisher = {mathdoc},
     volume = {2},
     number = {6},
     year = {1966},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DE_1966_2_6_a5/}
}