1. Department of Mathematics, University of the Punjab, Quaid-e-Azam Campus, Lahore 54590, Pakistan
2. Department of Mathematics, Near East University, TRNC, Mersin 10, Nicosia 99138, Turkey
3. Department of Mathematics, University of Cadiz, Puerto Real, Cádiz 11510, Spain
4. Department of Mathematics, King Abdulaziz University, P.O. Box 80203, Jeddah 21589, Saudi Arabia