%0 Journal Article %A Guzman, Adolfo W. %T Structural stability of polynomial second order differential equations with periodic coefficients %J Electronic Journal of Differential Equations %D 2004 %V 2004 %I mathdoc %U http://geodesic.mathdoc.fr/item/EJDE_2004__2004__a69/ %G en %F EJDE_2004__2004__a69