1. Department of Mathematics, Sonamukhi College, Bankura 722207, West Bengal, India,
2. Department of Mathematics, Kazi Nazrul University, Asansol 713340, West Bengal, India
3. Department of Mathematics, Midnapore College (Autonomous), Midnapore 721101, West Bengal, India,
4. Department of Applied Mathematics with Oceanology & Computer Programming, Vidyasagar University, Midnapore 721102 West Bengal, India,