@article{DE_1971_7_8_a19,
     author = {L. I. Zhilevich},
     title = {On the question of separatrices and limit cycles of a certain differential equation},
     journal = {Differencialʹnye uravneni\^a},
     pages = {1525--1527},
     publisher = {mathdoc},
     volume = {7},
     number = {8},
     year = {1971},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DE_1971_7_8_a19/}
}