1. Department of Mathematics, Saveetha School of Engineering, Saveetha Institute of Medical and Technical Sciences, Chennai 602105, Tamil Nadu, India
2. Department of Mathematics, Faculty of Engineering and Technology, SRM Institute of Science and Technology, SRM Nagar, Kattankulathur, Kanchipuram 603203, Tamil Nadu, India
3. Department of Mathematics, College of Natural and Applied Sciences, University of Dar es Salaam, Dar es Salaam 35063, Tanzania
4. Department of Mathematics, Ege University, Bornova, Izmir 35100, Turkey
5. Institute of Research and Development of Processes, Department of Electricity and Electronics, University of the Basque Country, 48940 Leioa, Spain