1. Department of Mathematics and Statistics, School of Basic Sciences, Manipal University Jaipur, Jaipur 303007, India
2. Department of Mathematics, Wollo University, P. O. Box 1145, Dessie, Ethiopia
3. Department of HEAS (Mathematics), Rajasthan Technical University, Kota 324010, India
4. Department of Computer Science and Mathematics, Lebanese American University, Beirut 03797751, Lebanon