1. Department of Mathematics, Faculty of Science, Islamic University of Madinah, Al Madinah 42351, Saudi Arabia
2. Department of Mathematics, Hajjah University, Hajjah 00967, Yemen
3. Department of Mathematics, University of Malakand, Chakdara Dir(L) 18000, Khyber Pakhtunkhawa, Pakistan
4. Department of Computer Science and Mathematics, Lebanese American University, Byblos P.O. Box 36, Lebanon