1. Faculty of Science, Department of Chemistry, Electrochemistry and Materials Chemistry, University of Dschang, Dschang, Cameroon
2. Department of Chemistry, Inorganic Chemistry Laboratory, University of Buea, Buea, Cameroon
3. School of Materials Sciences, Indian Association for the Cultivation of Science, Jadavpur, India
4. Department of Chemistry, Higher Teacher Training College, University of Yaoundé I, Yaoundé, Cameroon
5. Faculty of Science, Department of Chemistry, Laboratory of Analytical Chemistry, University of Yaoundé 1, Yaoundé, Cameroon