@article{DE_1974_10_6_a0,
     author = {N. P. Erugin},
     title = {The analytic and the qualitative theory, and also the asymptotic behavior of the solutions of the system $dx/dz=2\surd P(x,y)/z$, $dy/dz=2$ $\surd P(x,y)/(1-z)$. {I}},
     journal = {Differencialʹnye uravneni\^a},
     pages = {963--995},
     publisher = {mathdoc},
     volume = {10},
     number = {6},
     year = {1974},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DE_1974_10_6_a0/}
}