1. Anonymous (2000) Cameroon in figures 1999. Ministry of Economy and Finance. Dept. of Statistics and National Account. Republic of Cameroon. 28 pp.
2. Asawalam, D. O. (1997) Earthworm activity and nutrient cycling in agricultural systems in a humid tropical environment. Unpublished Ph. D. thesis, Department of Soil Science, University of Nigeria, Nsukka, Nigeria.
3. Effects of earthworm casts on crop production;Asawalam;Tropical Agriculture (Trinidad),2001
4. Earthworm surface casting activity on slash-and-burn cropped land and in undisturbed Chromolaena odorata and young forest fallow in southern Cameroon;Birang;Pedobiologia,2003
5. Büttner, U. (1996) Soil nutrient management practices of farmers in the humid forest region of Southern Cameroon. Unpublished Diploma dissertation, Department of Agriculture, Institute of Rural Development, Universität Göttingen.