Water Quality Standards Academy – U.S. Environmental Protection Agency 

USDA’s Water Quality Information Center – and wetlands information.

Constructed Wetlands and Water Quality Improvement – by Joe Makuch – USDA – 1992-1996 research cited  Water Quality Information Center

Wetlands and Water Quality – by Brian Miller – Indiana Dept. of Forestry – 1990
Purdue University Extension

Minnesota Wetlands Water Quality Standards Fact Sheet –  Minnesota Pollution Control Agency – 2005