1. School of Mathematical Sciences, Zhejiang Normal University, Jinhua, China
2. Centre for Advanced Studies in Pure and Applied Mathematics, Bahauddin Zakariya University Multan, Multan, Pakistan
3. Department of Mathematics, University of Sargodha, Sargodha, Pakistan
4. Department of Mathematics and Statistics, The University of Lahore, Sargodha Campus, Pakistan
5. Department of Maths and Computer Science, Faculty of Science, University of Kinshasa, Kinshasa, D. R. Congo
6. Department of Mathematics and Statistics, College of Science, Taif University, Taif, Saudi Arabia