1. Department of Basic Science, Institute of Information Technology, Modern Academy, Cairo, Egypt
2. Department of Mathematics, Faculty of Science, Cairo University, Giza, Egypt
3. Department of Mathematics and Computer Sciences, Cankaya University, Ankara, Turkey
4. Institute of Space Sciences, Magurele-Bucharest, Romania
5. Department of Mathematics, Faculty of Science, King Abdulaziz University, Jeddah, Saudi Arabia
6. Department of Mathematics, Faculty of Science, Beni-Suef University, Egypt