%0 Journal Article %T Meetings of the St. Petersburg Mathematical Society %J Trudy Matematicheskogo Instituta imeni V.A. Steklova %D 1999 %V 54 %N 1 %U http://geodesic.mathdoc.fr/item/RM_1999_54_1_a19/ %G ru %F RM_1999_54_1_a19