@article{DE_1976_12_12_a22,
     author = {L. A. Cherkas},
     title = {Absence of cycles in the equation $y'=Q_2(x,y)/P_2(x,y)$, with a focus of third degree of structural instability},
     journal = {Differencialʹnye uravneni\^a},
     pages = {2281--2282},
     publisher = {mathdoc},
     volume = {12},
     number = {12},
     year = {1976},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DE_1976_12_12_a22/}
}