1. Department of Mathematics, University of Sialkot, Sialkot 51310, Pakistan
2. Department of Mathematical Sciences, Karakoram International University Gilgit, Gilgit 15100, Pakistan
3. Department of Mathematics, University of Management and Technology, Lahore, Sialkot Campus, Pakistan
4. Department of Mathematics, Faculty of Mathematical and Computer Science, University of Gezira, Wad Madani, Sudan