T. Mathivanan, Research Scholar, Research Department of Mathematics, St. Xavier's College (Autonomous), Palayamkottai - 627 002. India.

Reference:
Dr. A. Lourdusamy,
Associate Professor,
Department of Mathematics,
St. Xavier's College (Autonomous),
Palayamkottai - 627 002.
India.
Email: lourdusamy15@gmail.com