1. Department of Mathematics, Vishnu Institute of Technology, Bhimavaram, West Godavari, 534302, Andhra Pradesh, India
2. Department of Mathematics, Annamalai University, Annamalai Nagar, 608002, Tamilnadu State, India
3. Department of Mathematics, S. R. K. R. Engineering College, Bhimavaram, West Godavari, 534201, Andhra Pradesh, India