%0 Journal Article %A Heinrich Steinlein %T On the Index of Approximating Sets of Periodic Points. %J Manuscripta mathematica %D 1996 %P 15-34 %V 89 %N 3 %I mathdoc %U http://geodesic.mathdoc.fr/item/MM2_1996__89_3_156147/ %F MM2_1996__89_3_156147