1. Department of Mathematics, Maharaja Agrasen University, Baddi, Solan, Himachal Pradesh, India
2. Department of Mathematics, PRS Govt. College Baijnath, Kangra, Himachal Pradesh, India
3. Department of Mathematics, Dinabandhu Mahavidyalaya, Bongaon, West Bengal, India
4. Department of Applied Mathematics, University of Calcutta, Kolkata, West Bengal, India