1. University of Yaounde I, Faculty of Science, Department of Physics, P.O. Box 812, Yaounde, Cameroon
2. CETIC (Centre d’Excellence Africain en Technologies de l’Information et de la Communication), Université de Yaoundé I, B.P. 8390, Yaoundé, Cameroon
3. University of Bamenda, National Higher Polytechnic Institute, Department of Electrical and Electronic Engineering, P. O. Box 39, Bambili, Cameroon
4. University of Dschang, IUT Bandjoun, Department of General and Scientific Studies, P.O. Box 134, Bandjoun, Cameroon
5. University of Yaounde I, Faculty of Science, Department of Chemistry, P.O. Box 812, Yaounde, Cameroon