@article{DE_1994_30_3_a1,
     author = {L. I. Zhilevich},
     title = {On the existence of a limit cycle in an autonomous system},
     journal = {Differencialʹnye uravneni\^a},
     pages = {377--380},
     publisher = {mathdoc},
     volume = {30},
     number = {3},
     year = {1994},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DE_1994_30_3_a1/}
}