1. Applied Inorganic Chemistry Laboratory, Department of Inorganic Chemistry, Faculty of Sciences, University of Yaoundé 1, P.O. Box: 812 Yaoundé, Cameroon
2. Laboratory of Materials Physicochemistry and Environment, Department of Chemistry, Faculty of Sciences Semlalia Marrakech, University of Cadi Ayyad, Boulevard Prince Moulay Abdellah, BP: 2390 – 40000 Marrakech, Maroc
3. Institute of Fine Arts of Foumban, University of Dschang, BP: 31 Foumban, Cameroon
4. Research Institute on Ceramics, University of Limoges, CEC, 12 Rue Atlantis 87068 Limoges, France