1. Advanced Teacher’s Training College for Technical Education, Engineering Sciences Doctoral Training Unit, Laboratory of Forest and Wood Resources Valorisation, University of Douala, Douala, Cameroon
2. CNRS, Institut Pascal, Université Clermont Auvergne, Clermont-Ferrand, France
3. CENAREST, IRT, Libreville, Gabon
4. Advanced Teacher’s Training College for Technical Education, Engineering Sciences Doctoral Training Unit, Laboratory of Mechanic, University of Douala, Douala, Cameroon