1. Department of Mathematics and Statistics, College of Science Al‐Imam Muhammad Ibn Saud Islamic University Riyadh Saudi Arabia
2. Department of Mathematics, Faculty of Sciences Umm Al‐Qura University Makkah Saudi Arabia
3. Department of Mathematics, Faculty of Science University of Tunis El Manar Tunis Tunisia
4. Faculty of Applied Mathematics AGH University of Kraków Kraków Poland
5. Department of Mathematics University of Craiova Craiova Romania
6. Faculty of Electrical Engineering and Communication Brno University of Technology Brno Czech Republic
7. School of Mathematics Zhejiang Normal University Jinhua China
8. Simion Stoilow Institute of Mathematics of the Romanian Academy Bucharest Romania