1. Laboratoire d’Automatique et d’Informatique Appliquée (LAIA), IUT-FV of Bandjoun, The University of Dschang, P. O. Box 134, Bandjoun, Cameroon
2. Laboratory of Mechanics, Department of Physics, Faculty of Sciences, The University of Yaounde I, P. O. Box 812, Yaoundé, Cameroon
3. Faculty of Science, Taibah University, Al-Madinah Al-Munawarah, Saudi Arabia
4. Mathematics Department, Faculty of Science, Beni-Suef University, Egypt