1. Institute for Systems Theory and Automatic Control, University of Stuttgart, Pfaffenwaldring 9, 70550 Stuttgart, Germany
2. Department of Economics, Society and Politics, University of Urbino, via Saffi 42, 61029 Urbino, Italy
3. Department of Physics, The Technical University of Denmark, Fysikvej 309, 2800 Lyngby, Denmark
4. Department of Computer Science, Southwest State University, 50 Years of October Str., 94, 305040 Kursk, Russia