1. Department of Chemistry, Organic and Bioorganic Chemistry, Bielefeld University
2. Department of Chemistry, Higher Teachers' Training College, University of Yaoundé 1
3. Institute of Forestry, Tribhuvan University
4. Department of Organic Chemistry, Faculty of Science, University of Yaoundé 1
5. Department of Biochemistry, Faculty of Science, University of Yaoundé
6. H.E.J. Research Institute of Chemistry, International Center for Chemical and Biological Sciences, University of Karachi
7. Division of Infectious Diseases, Department of Medicine, University of California