1. Department of Mathematics, Riphah International University (Lahore Campus), Lahore 54000, Pakistan
2. Faculty of Organizational Sciences, University of Belgrade, Belgrade 11000, Serbia
3. College of Engineering, Yuan Ze University, Taoyuan, Taiwan
4. Department of Mathematics, Kabul Polytechnic University, Kabul, Afghanistan
5. Mathematical Institute of the Serbian Academy of Sciences and Arts, Kneza Mihaila 36, Belgrade 11000, Serbia