%0 Journal Article %A Jonathan M. Wahl %T Derivations of Negative Weight and Non-Smoothability of Certain Singularities. %J Mathematische Annalen %D 1981 %P 383-398 %V 258 %I mathdoc %U http://geodesic.mathdoc.fr/item/MAN_1981__258_163605/ %F MAN_1981__258_163605