1. Department of Mathematics, Abdul Wali Khan University, Mardan, Khyber Pakhtunkhwa, Pakistan
2. School of Finance and Economics, Jiangsu University, Zhenjiang, Jiangsu, People's Republic of China
3. Department of Mathematical Sciences, University of Lakki Marwat, Lakki Marwat, Khyber Pakhtunkhwa, Pakistan
4. Department of Quantitative Analysis, College of Business Administration, King Saud University, Riyadh, Saudi Arabia