%0 Journal Article %A W. Szlenk %T On non-smoothly equivalent diffeomorphisms of the circle %J Colloquium Mathematicum %D 1974 %P 257-259 %V 32 %N 2 %I mathdoc %U http://geodesic.mathdoc.fr/articles/10.4064/cm-32-2-257-259/ %R 10.4064/cm-32-2-257-259 %G en %F 10_4064_cm_32_2_257_259