1. Department of Applied Mathematics, School of Applied Natural Sciences, Adama Science and Technology University, Post Box No.1888, Adama, Ethiopia
2. Department of Mathematics, Vignan’s Foundation for Science, Technology & Research, Vadlamudi-522213, Andhra Pradesh, India.
3. Department of Basic Science and Humanities, Vignan Lara Institute of Technology and Science, Vadlamudi-522213, Andhra Pradesh, India