1. University Institute of Technology, University of Ngaoundere, Cameroon
2. International Centre of Insect Physiology and Ecology (ICIPE), Nairobi, Kenya
3. Chemistry Department, School of Pure and Applied Sciences, Kenyatta University, Nairobi, Kenya
4. Department of Organic Chemistry, Faculty of Science, University of Yaoundé, Cameroon
5. Department of Chemistry, Faculty of Science, University of Buea
6. Department of Chemistry, Higher Teacher Training College, University of Yaoundé I, Cameroon
7. Department of Organic Chemistry, Faculty of Science, University of Dschang, Cameroon
8. Institute of Organic Chemistry, BMWZ, Leibniz University Hannover, Germany