1. Institute of Mathematics, National Academy of Sciences of Ukraine, 3 Tereshchenkivska St., 01024 Kyiv, Ukraine
2. Institute for Systems Theory and Automatic Control, University of Stuttgart, Pfaffenwaldring 9, 70550 Stuttgart, Germany
3. Department of Economics, Society, Politics (DESP), University of Urbino, Via A. Saffi n.42, 61029 Urbino, Italy