1. Department of Mathematics, Lahore College for Women University, Lahore, Pakistan
2. Department of Mathematics, COMSATS University Islamabad, Lahore Campus, Pakistan
3. Department of Mathematics, Government College University, Faisalabad, Pakistan
4. Basic Science Department, Preparatory Year Deanship, King Faisal University, Al Ahsa, Saudi Arabia
5. Department of Mathematics, Addis Ababa University, Addis Ababa, Ethiopia