1. Department of Mathematical Science, Faculty of Science, Princess Nourah Bint Abdulrahaman University, Riyadh, Saudi Arabia
2. Department of Mathematics, Kabi Sukanta Mahavidyalaya, The University of Burdwan, Bhadreswar, Angus, Hooghly, Pin, West Bengal, India
3. Department of Pure Mathematics,University of Calcutta, Kolkata, West Bengal, India