1. 1Kuwait College of Science and Technology, Doha District, Block 4, P.O. Box 27235, Safat 13133, Kuwait University of Primorska, FAMNIT, Glagoljsaška 8, 6000 Koper, Slovenia
2. 2School of Mathematics and Statistics, University of Melbourne, Victoria 3010, Australia
3. 3Faculty of Economics, University of Debrecen, Hungary