1. Department of Mathematics, University of Engineering and Technology, Lahore 54890, Pakistan
2. Department of Mathematics & Statistics, Jordan University of Science and Technology, P.O. Box 3030, Irbid 22110, Jordan
3. Department of Mathematics, College of Sciences, King Khalid University, Abha 61413, Saudi Arabia
4. Department of Mathematics, COMSATS University Islamabad, Sahiwal 57000, Pakistan