1. Department of Chemistry, Higher Teacher Training College, The University of Bertoua, P.O. Box 652, Bertoua, Cameroon
2. Department of Chemistry, Faculty of Science, The University of Maroua, P.O. Box 814, Maroua, Cameroon
3. University Institute of Wood Technology of Mbalmayo, University of Yaoundé I, P.O. Box 306, Mbalmayo, Cameroon
4. Department of Chemistry, Faculty of Science, The University of Bamenda, P.O. Box 39, Bambili-Bamenda, Cameroon