%0 Journal Article %A Yu. S. Ilyashenko %T The nonalgebraic character of the manifold of differential equations with rational right-hand sides and with multiple limit cycles %J Sbornik. Mathematics %D 1970 %P 453-457 %V 12 %N 3 %I mathdoc %U http://geodesic.mathdoc.fr/item/SM_1970_12_3_a6/ %G en %F SM_1970_12_3_a6