1. Department of Basic Sciences, University of Engineering and Technology, Taxila, Pakistan
2. Department of Mathematics, COMSATS University Islamabad, Wah Campus, Pakistan
3. Section of Mathematics, International Telematic University Uninettuno, Roma, Italy
4. Department of Physics and Astronomy, College of Science, King Saud University, Riyadh, Saudi Arabia
5. Industrial Engineering Department, College of Engineering, King Saud University, Riyadh, Saudi Arabia