1. Department of General Education, Anhui Xinhua University, Hefei, China
2. Department of Mathematics, Islamia College, Peshawar, Khyber Pakhtunkhwa, Pakistan
3. Department of Mathematics, COMSATS University Islamabad, Lahore Campus, Pakistan
4. Department of Mathematics, Abbottabad University of Science and Technology, Abbottabad, Khyber Pakhtunkhwa, Pakistan
5. Department of Mathematics, University of Ghana, Legon, Ghana