1. Reversing the Spiral: The Population, Agriculture, and Environment Nexus in Sub-Saharan Africa;Cleaver,1994
2. Soil Map of Africa, Scale l: 5,000,000. Joint Project No. 11;D'Hoore,1964
3. Classification and management of Histosols;Eswaran,1986
4. Land Degradation and Sustainable Agriculture: A Global Perspective;Eswaran,1994
5. Oxisols of the World;Eswaran,1986