1. Mathematics Department, Faculty of Science, Taif University, Hawia, 888 Taif, Saudi Arabia.
2. Mathematics Department, Faculty of Science, Al-Azhar University, Nasr City, 11884 Cairo, Egypt.
3. Mathematics Department, Faculty of Science and Arts, Khulais, King Abdulaziz University (KAU), Saudi Arabia.
4. Mathematics Department, Faculty of Science, Al-Azhar University (Assiut Branch), Assiut, Egypt.