1. Department of Mathematics, Faculty of Arts and Science, Khalifa University , P.O. Box: 127788 , Abu Dhabi , UAE
2. College of Engineering and Technology, American University of the Middle East , Egaila 54200 , Kuwait
3. NAAM Research Group, Department of Mathematics, Faculty of Science, King Abdulaziz University , P.O. Box 80203 , Jeddah 21589 , Saudi Arabia