1. Department of Mathematics, King Saud University, Riyadh, Saudi Arabia
2. Department of Mathematics, Division of Science and Technology, University of Education, Lahore, Pakistan
3. Department of Mathematics, College of Science & Arts, King Abdulaziz University, Rabigh, Saudi Arabia
4. Department of Mathematics, Government College University Faisalabad, Faisalabad, Pakistan
5. School of Mathematics and Physics, Anhui Jianzhu University, Hefei, China