%0 Journal Article %A Manchón, P. M. G. %T Hypersurfaces in $\mathbb R^n$ and critical points in their external region %J Czechoslovak Mathematical Journal %D 2002 %P 1-9 %V 52 %N 1 %I mathdoc %U http://geodesic.mathdoc.fr/item/CMJ_2002__52_1_a0/ %G en %F CMJ_2002__52_1_a0