1. Geovalmma Consulting Limited, Yaoundé, Cameroon
2. Institute for Mineral Resources, Technische Universität Clausthal, Clausthal–Zellerfeld, Germany
3. Department of Geology, Faculty of Science, Benha University, Benha, Egypt
4. Geological Survey of Denmark and Greenland, Copenhagen K, Denmark
5. Department of Earth Sciences, University of Stellenbosch, Stellenbosch, South Africa
6. School of Earth, Atmospheric and Environmental Sciences, University of Manchester, Manchester, UK
7. Department of Geology and Environmental Sciences, University of Buea, Buea, Cameroon