1. Department of Mathematics, Faculty of Engineering and Technology, College of Engineering and Technology, SRM Institute of Science and Technology, SRM Nagar, Kattankulathur -603203, TN, India
2. Department of Mathematics and General Sciences, Prince Sultan University, P. O. Box 66833, Riyadh 11586, Saudi Arabia
3. Department of Mathematics, Bharathiar University, Coimbatore-641046, TN, India