1. Department of Mathematical Sciences, Faculty of Sciences, Princess Nourah bint Abdulrahman University , P.O. Box 84428 , Riyadh 11671 , Saudi Arabia
2. Department of Basic Sciences, Preparatory Year Deanship, King Faisal University , Al Ahsa 31982 , Saudi Arabia
3. Department of Basic Sciences, Preparatory Year Deanship, King Faisal University , P.O. Box 400 , Hofuf , Al-Ahsa 31982 , Saudi Arabia
4. Department of Mathematics, Abdul Wali University Mardan , Mardan , Pakistan