1. Department of Mathematics , University of North Alabama , Florence , AL 35632 , Usa
2. Department of Mathematics and Statistics , Auburn University , 221 Parker Hall , Auburn , AL , Usa
3. Deanship of Preparatory Year and Supporting , Studies Imam Abdulrahman Bin Faisal University Dammam , Dammam, K , Saudi Arabia
4. Department of Mathematics and Natural Sciences , American University of Ras Al Khaimah Ras Al Khaimah , Khaimah , Uae
5. Department of Mathematics and Statistics , Auburn University Auburn , Auburn , AL 36849 , Usa