1. Department of Physics; Acharya Nagarjuna University; Nagarjuna Nagar AP India
2. Faculty of Physics; Opole University of Technology; Opole Poland
3. Institute of Physics; Mathematical and Natural Science Department; Jan Dlugosz University; Czestochowa Poland
4. College of Sciences; Chongqing University of Posts and Telecommunications; Chongqing China
5. Institute of Physics; University of Tartu; Tartu Estonia