1. Res Inst of Appl Math and Cybernetics, Nizhny Novgorod State Univ, Russia
2. Inst for Prob in Mech, Russian Acad of Sci, Moscow, Russia
3. Dept of Mech and Aerospace Eng, Univ of Virginia, Charlottesville VA, Russia
4. Dept of Mech and Aeronaut Eng, Clarkson Univ, CAMP 241, Box 5725, Potsdam NY 13699-5725