1. Chemical analysis of ecological materials;Allen,1989
2. Heavy metals in soils;Alloway,1990
3. The behaviours of heavy metals in sewage sludge-amended soil;Alloway;Sci. Total Environ.,1991
4. The nature and properties of soils;Brady,1974
5. Liming effects on availability of Cd, Cu, Ni and Zn in a soil amendment with sewage sludge 16 years previously;Brallier;Water Air Soil Pollut.,1994