Affiliation: Department of Stochastics, Institute of Mathematics,
Budapest University of Technology and Economics
E-mail address: marib@math.bme.hu
Phone number: 36-1-463-1111, extension 5902
Fax number: 36-1-463-1677
Postal address: H-1521 Budapest, P.O.Box 91, Bldg H. 5/7.
Hungary