1. Department of Mathematics and Computer Science, Avram Iancu University of Cluj-Napoca, Romania
2. Romanian Institute of Science and Technology, Cluj-Napoca, Romania
3. Department of Mathematical Analysis and Numerical Mathematics, Comenius University in Bratislava, Slovakia
4. Mathematical Institute Slovak Academy of Sciences, Bratislava, Slovakia
5. Department of Applied Cybernetics, Saint-Petersburg State University, Russia
6. University of Jyväskylä, Finland
7. Department of Electronic Engineering, City University of Hong Kong, Hong Kong SAR, P. R. China