1. Department of Mathematics and statistics, Lahore Garrison University, Lahore 54000, Pakistan
2. Department of Mathematics, COMSATS University Islamabad, Lahore Campus, Lahore 54000, Pakistan
3. Department of Mathematics, Virtual University of Pakistan, Lahore Campus, 54-Lawrence Road, Lahore 54000, Pakistan
4. Department of Mathematics, Iran University of Science and Technology (IUST), Narmak, Tehran 16844, Iran
5. Department of Mathematics, Faculty of Computer Science and Mathematics, University of Kufa, Najaf, Iraq