@article{DE_1977_13_3_a8,
     author = {P. T. Cherevichny},
     title = {The index of a singular point of the equation $y'=\frac{P_4(x,y)}{Q_4(x,y)}$},
     journal = {Differencialʹnye uravneni\^a},
     pages = {463--467},
     publisher = {mathdoc},
     volume = {13},
     number = {3},
     year = {1977},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DE_1977_13_3_a8/}
}