| Affiliation: | 1. Department of Mathematics , Quaid-i-Azam University 45320 , Islamabad 44000 , Pakistan noreensher@yahoo.com;3. Department of Mathematics , Quaid-i-Azam University 45320 , Islamabad 44000 , Pakistan;4. Department of Mathematics , Quaid-i-Azam University 45320 , Islamabad 44000 , Pakistan;5. Faculty of Science, Department of Physics , King Saud University , P.O. Box 1846, Riyadh 11321 , Saudi Arabia;6. Faculty of Science, Department of Physics , King Saud University , P.O. Box 1846, Riyadh 11321 , Saudi Arabia |
