1. School of Information Science and Engineering, Chengdu University, Chengdu 610106, China
2. Department of Mathematics, Division of Science and Technology, University of Education Lahore, Lahore, Pakistan
3. Department of Mathematics, COMSAT University, Vehari Campus, Vehari, Pakistan
4. Department of Mathematics and Statistics, The University of Lahore, Lahore, Pakistan
5. Department of Basic Science and Humanities, University of Engineering and Technology, Lahore, Narowal Campus, Pakistan