1. Mathematics Department, Faculty of Science, Al-Azhar University, Nasr City 11884, Cairo, Egypt
2. Department of Mathematics, College of Science, Taif University, P.O. Box 11099, Taif 21944, Saudi Arabia
3. Mathematics Department, Faculty of Science (Girls Branch), Al-Azhar University, Nasr City 11884, Cairo, Egypt
4. Department of Mathematics and Computer Science, Faculty of Science, Menoufia University, Shebin Elkom 32511, Egypt