%0 Journal Article %A Alwash, Mohamad A.M. %T Periodic solutions of polynomial non-autonomous differential equations %J Electronic Journal of Differential Equations %D 2005 %V 2005 %I mathdoc %U http://geodesic.mathdoc.fr/item/EJDE_2005__2005__a31/ %G en %F EJDE_2005__2005__a31