1. Analyses of profile samples of differing productivity;Ayed;Sudan Agric. J.,1968
2. Vertisols in the Gezira and the Khasma el Girba clay plains;Blokhuis,1964
3. Soils of Central Sudan;Buursink,1970
4. Soil structure in Vertisols of the Blue Nile Clay Plains, Sudan;De Vos;J. Soil Sci.,1969
5. Classification of Gezira clay soil;Finck;Soil Sci.,1961