1. Department of Mathematics, Acharya Nagarjuna University, Guntur, Andhra Pradesh 522510, India
2. Department of Mathematics, Swarnandhra Institute of Engineering and Technology, Seetharamapuram, Narasapuram, West Godhavari District, Andhra Pradesh 534275, India
3. Faculty of Engineering, Kuwait College of Science and Technology, Doha District 35004, Kuwait