Zolotarev Sergei Alekseevitsch

Publications in Math-Net.Ru

1. On the problem of distinguishing the center and focus in a certain case
   
   Differ. Uravn., 27:11 (1991),  1852–1862
2. Some cases of the integrability of differential equations of the form $y''+p(x)y'+h(x)y+f(x)F(y,k(x))=0$
   
   Differ. Uravn., 21:4 (1985),  720–724