1. School of Mathematics & Computer Science, Shangrao Normal University, Shangrao 334001, China
2. Department of Mathematics, University of Sargodha, Sargodha 40100, Pakistan
3. School of Mathematical Sciences, Universiti Sains Malaysia, Penang 11800, Malaysia
4. Department of Mathematics and Statistics, College of Science, Taif University, P.O. Box 11099, Taif 21944, Saudi Arabia