1. Department of Mathematics, Govt. M.A.O College Lahore, Lahore, Pakistan
2. GC University, Lahore, Pakistan
3. Department of Mathematics, COMSATS University Islamabad, Vehari Campus, Vehari, Pakistan
4. Department of Mathematics, Government Islamia College Lahore, Lahore, Pakistan
5. Department of Mathematics, COMSATS University Islamabad, Attock Campus, Attock, Pakistan