1. Department of Mathematics, Kabi Jagadram Roy Government General Degree College, Mejia, Gopalpur, West Bengal, India
2. Institute of Natural Sciences and Applied Technology, Kolkata, India
3. Department of Physics, Guru Nanak Dev University at Amritsar, Amritsar, Punjab, India
4. Department of Mathematics, Visva-Bharati University, Santiniketan, West Bengal, India