1. Department of Mathematics, Abdul Wali Khan University, Mardan, Khyber Pakhtunkhwa, Pakistan
2. Department of Mathematics and Statistics, Bacha Khan University, Charsadda, Khyber Pakhtunkhwa, Pakistan
3. Department of Mathematics and Statistics, Hazara University, Mansehra, Khyber Pakhtunkhwa, Pakistan
4. Sarhad University of Science and Information Technology, Peshawar, Khyber Pakhtunkhwa, Pakistan