%0 Journal Article %A Toni, B. %T Higher order branching of periodic orbits from polynomial isochrones %J Electronic Journal of Differential Equations %D 1999 %V 1999 %I mathdoc %U http://geodesic.mathdoc.fr/item/EJDE_1999__1999__a21/ %G en %F EJDE_1999__1999__a21