1. Dynamics and Vibration, Institute of Thermomechanics, Academy of Sciences of the Czech Republic, Dolejškova 1402/5, Prague 18200, Czech Republic
2. Nonlinear Modelling, Institute of Computer Science, Academy of Sciences of the Czech Republic, Pod Vodárenskou věží 271/2, Prague 18207, Czech Republic
3. EMTD Measurement Ltd., 9 Brookside Avenue, Nottingham NG82RD, UK