%0 Journal Article %A Ch.H. Giffen %T Diffeotopically Trivial Periodic Diffeomorphisms. %J Inventiones mathematicae %D 1970 %P 340-348 %V 11 %I mathdoc %U http://geodesic.mathdoc.fr/item/IM_1970__11_142062/ %F IM_1970__11_142062