1. Trace metals in the environment: retrospect and prospect;Davies,1992
2. A silent epidemic of environmental metal poisoning?;Nriagu;Environ. Pollution,1988
3. Environmental Chemistry of the Elements;Bowen,1979
4. Cycling of metal ions in the soil environment;Sposito;Metal Ions in Biological Systems, Circulation of Metals in the Environment,1984
5. Trace Elements in the Terrestrial Environment;Adriano,1986