1. Faculty of Computer Science and Information, Technology, Northern Border University, Rafha, Kingdom of Saudi Arabia
2. Mathematics Department, Faculty of Sciences, University of Tunis, El-Manar, 1060 Tunis, Tunisia
3. Department of Mathematics, Faculty of Science, King Abdulaziz University, P.O. Box 80203, 21589 Jeddah, Kingdom of Saudi Arabia
4. Faculty of Education and Faculty of Mathematics and Physics, University of Ljubljana & Institute of Mathematics, Physics and Mechanics, 1000 Ljubljana, Slovenia