1. Mathematics Department, Faculty of Science, Taif University, Taif, Saudi Arabia;
2. Mathematics Department, Faculty of Science, South Valley University, Qena, Egypt;
3. Mathematics Department, Faculty of Science, Cairo University, Giza, Egypt;
4. Mathematics Department, Faculty of Science, Sohag University, Sohag, Egypt;
5. Mathematics Department, Faculty of Science, King Khalid University, Al-Namas, Saudi Arabia