1. Sulphur Status of Some Soils of East Central State of Nigeria;Aghimien,1975
2. West African Soils;Ahn,1970
3. Incidence of sulphur deficiency in Africa;Bolle-Jones,1964
4. Directions for making mechanical analysis of soils by the hydrometer method;Bouyoucos;Soil Sci.,1936
5. Turbidimetric determination of available sulphate;Chensin,1950