1. Department of Economics, Birmingham Business School, College of Social Sciences, University of Birmingham, Edgbaston B152TT, UK
2. Department of Mathematics and Statistics, Hazara University Mansehra, Pakistan
3. Department of Civil Engineering, College of Engineering, King Khalid University, Abha 61421, Saudi Arabia
4. Department of Chemistry, College of Science, King Khalid University, Abha 61413, Saudi Arabia
5. Department of Statistics, University of Peshawar, Pakistan