%0 Journal Article %T International Conference on Modern Problems in Quantum Field Theory, Strings and Quantum Gravity %J Teoretičeskaâ i matematičeskaâ fizika %D 1993 %P 179-182 %V 95 %N 2 %I mathdoc %U http://geodesic.mathdoc.fr/item/TMF_1993_95_2_a0/ %G en %F TMF_1993_95_2_a0