1. Department of Chemistry, Organic and Bioorganic Chemistry, Bielefeld University
2. Institute of Forestry, Pokhara Campus, Tribhuvan University
3. Higher Teacher's Training College, University of Yaoundé I
4. H.E.J. Research Institute of Chemistry, International Center for Chemical and Biological Sciences, University of Karachi
5. Department of Biochemistry, Faculty of Science, University of Yaoundé I