@article{DE_1972_8_10_a8,
     author = {I. G. Rozet},
     title = {Coefficient criteria for the existence of separatrix cycles for a certain quadratic equation},
     journal = {Differencialʹnye uravneni\^a},
     pages = {1791--1796},
     publisher = {mathdoc},
     volume = {8},
     number = {10},
     year = {1972},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DE_1972_8_10_a8/}
}