@article{DE_1983_19_5_a18,
     author = {G. S. Rychkov},
     title = {Uniqueness of the limit cycle of the equation $(y-P_3(x))dy=P_1(x,y)dx$ in the presence of three singular points},
     journal = {Differencialʹnye uravneni\^a},
     pages = {904--905},
     publisher = {mathdoc},
     volume = {19},
     number = {5},
     year = {1983},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DE_1983_19_5_a18/}
}