1. Department of Mechanical Engineering Science, Faculty of Engineering and the Built Environment, University of Johannesburg, Johannesburg, South Africa
2. Department of Medical Research, China Medical University, Taichung 404, Taiwan
3. Department of Mathematics and Informatics, National University of Science and Technology Politehnica Bucharest, Bucharest 060042, Romania
4. Department of Mathematics, Government College University Lahore, Lahore 54000, Pakistan
5. Department of Mathematics, Federal University of Technology, Owerri, Nigeria
6. Abdus Salam School of Mathematical Sciences, Lahore 54000, Pakistan