1. Department of Applied Mathematics, University of Agriculture in Krakow, Al. Mickiewicza 21, 31-120 Kraków, Poland
2. Institute of Mathematics of NAS of Ukraine, 3 Tereschenkivska Str., Kyiv 01024, Ukraine
3. Department of Computational Mathematics and Programming, Institute of Applied Mathematics and Fundamental Sciences, Lviv Polytechnic National University, 12 Bandera Str., 79013 Lviv, Ukraine
4. Department of Mathematics, Institute of Applied Mathematics and Fundamental Sciences, Lviv Polytechnic National University, 12 Bandera Str., 79013 Lviv, Ukraine
5. Department of Information Systems, Faculty of Management, Comenius University in Bratislava, Odbojárov 10, 82005 Bratislava, Slovakia