1. Genesis and Hardening of Laterite in Soils;Alexander,1962
2. Composition and soil genesis;Allen,1983
3. Chlorites and hydroxy interlayered vermiculite and smectite;Barnhisel,1977
4. Methods of Chemical Analysis for Soils and Waters;Begheijn,1980
5. Land in Sierra Leone: A Reconnaissance Survey and Evaluation for Agriculture;Birchall,1979