1. School of Geology and Mining Engineering, University of Ngaoundere, Meiganga, Cameroon
2. Université Côte d’Azur, CNRS, Observatoire de la Côte d’Azur, IRD, Valbonne, France
3. Department of Physics, Faculty of Science, University of Douala, Douala, Cameroon
4. Mines Alès Institute, Alès, France
5. National Centre of Excellence in Geology (NCEG), University of Peshawar, Peshawar, Pakistan
6. Department of Physics, University of Yaounde I, Yaounde, Cameroon
7. School of Mines and Geosciences, University of Dar es Salaam, Dar es Salaam, Tanzania