1. Department of Mathematics, COMSATS University Islamabad, Islamabad 44000, Pakistan
2. Department of Electrical Engineering, College of Engineering, Taif University, P. O. Box 11099, Taif 21944, Saudi Arabia
3. Department of Applied Mathematics, University Politehnica of Bucharest, 060042 Bucharest, Romania
4. Academy of Romanian Scientists, 54 Splaiul Independentei, 050094 Bucharest, Romania
5. Fundamental Sciences Applied in Engineering - Research Center (SFAI), University Politehnica of Bucharest, 060042 Bucharest, Romania
6. Nonlinear Analysis and Applied Mathematics-Research Group, Department of Mathematics, Faculty of Sciences, King Abdulaziz University 21589-Jeddah, Saudi Arabia
7. Department of Mathematics, Faculty of Science, Khon Kaen University, Khon Kaen 40002, Thailand