1. Stream ecology: Structure and function of running waters;Allan,1995
2. The importance of trace metal speciation to water quality criteria;Allen;Water Environ. Res.,1996
3. American Public Health Association, American Water Works Association, Water pollution control Federation, 1998. Standard Methods for the Examination of Water and Wastewater, Twentieth ed. Washington, DC.
4. Trace metal speciation of labile chemical species: Other methods;Apte,1995
5. Arkansas Geological Commission, 2005. Available at http://www.state.ar.us/agc/stratigr.html Accessed September 27, 2005.