1. Science and technology for defense lab LR19DN01, center for military research, military academy, Tunis, Tunisia
2. Military Aeronautical Specialities School, Sfax, Tunisia
3. Department of Mathematics, University of Sfax, Faculty of Science of Sfax, Sfax, Tunisia
4. Mathematics Departement, Faculty of Science of Tunis, University of Tunis El Manar, Tunisia
5. Department of Mathematics, FSTH Abdelmalek Essaadi University-Tetuan, Morocco
6. Department of Mathematics, Mohammed I University, Oujda, Morocco