%0 Journal Article %A B. Sh. Mordukhovich %T Penalty functions and necessary conditions for an~extremum in non-smooth and non-convex optimization problems %J Trudy Matematicheskogo Instituta imeni V.A. Steklova %D 1981 %P 242-243 %V 36 %N 1 %I mathdoc %U http://geodesic.mathdoc.fr/item/RM_1981_36_1_a14/ %G en %F RM_1981_36_1_a14