1. Department of Mathematics University of Wah, Wahcantt 47040, Pakistan
2. Department of Mathematics, The University of Faisalabad, Sargodha Road, University Town Faisalabad, Punjab 38000, Pakistan
3. Department of Mathematics and Statistics, International Islamic University, Islamabad 46000, Pakistan
4. Department of Mathematics, Abdul Wali Khan University, Mardan, KP, Pakistan
5. Department of Mathematics, Sanna University, Sana’a, Yemen