1. Cornet, A. and Poupon, H. (1977) Description of Environmental factors and Vegetation in Five Plots Located along a Climatic Gradient in the Sahelian Zone in Senegal. IFAN Bulletin, 39, 241-302.
2. Breman, H. and De Ridder, N. (1991) Manual on Pastures in the Sahelian Countries. KARTHALA, ACCT, CABO-DLO and CTA, Paris and Wageningen, 485 p.
3. Coulibaly, A. (1979) Phyto-Ecological and Phytosociological Approach to Sahelian Pastures in Mali (Gourma Region). Postgraduate Thesis, University of Nice, Nice, 149 p.
4. Penning de Vries, F.W.T. and Djitéye, M.A. (1991) La productivité des paturages sahéliens. Pudoc, Wageningen.
5. Soil and crop growth micro-variability in the West African semi-arid tropics: a possible risk-reducing factor for subsistence farmers