1. Department of Statistics, Sri Venkateswara University, Tirupati 517502, Andhra Pradesh, India.
2. Department of Mathematics & Scientific Computing, National Institute of Technology, Hamirpur, Hamirpur 177005, Himachal Pradesh, India
3. Department of Humanities & Sciences, S. V. Engineering College, Tirupati 517507, Andhra Pradesh, India.
4. Department of Statistics, Sri Venkateswara Unviversity, Tirupati 517502, Andhra Pradesh, India.