1. U.S. EPA. Summary of the Clean Water Act. 2019. Available from: https://www.epa.gov/laws-regulations/summary-clean-water-act; and https://www.epa.gov/sites/production/files/2017-08/documents/federal-water-pollution-control-act-508full.pdf
2. U.S. General Accounting Office. Better Monitoring Techniques Are Needed to Assess the Quality of Rivers and Streams. Volume 1. CED-81-30. Washington, DC: U.S. General Accounting Office; 1981
3. National Research Council. Environmental Monitoring. Washington, DC: Volume IV. National Academy of Sciences; 1977
4. U.S. Environmental Protection Agency. Surface Water Monitoring: A Framework for Change. Washington, DC: Water Office; 1987
5. U.S. Environmental Protection Agency. Report of the National Workshop on Instream Biological Monitoring and Criteria. Corvallis, OR: Environmental Research Laboratory-Corvallis; 1987