1. Department of Mathematics, Nawab Shah Alam Khan College of Engineering and Technology, Hyderabad 500024, Telangana, India
2. Department of Mathematics, Jawaharlal Nehru Technological University Hyderabad, College of Engineering, Jagtial 505501, Telangana, India
3. Department of Mathematics, Chaitanya Bharathi Institute of Technology, Gandipet, Hyderabad 500075, Telangana, India