1. Department of Mathematics and Statistics, Hazara University Mansehra, Mansehra, Pakistan
2. Department of Mathematics, Faculty of Arts and Sciences, Yildiz Technical University, Esenler 34210, Istanbul, Turkey
3. Department of Mathematics and Statistics, International Islamic University Islamabad, Islamabad, Pakistan
4. Faculity of Organizational Sciences, University of Belgrade, Belgrade, Serbia
5. Department of Mathematics, University of Gondar, P.O. Box: 196, Gondar, Ethiopia