@article {71, title = {National Recommended Water Quality Criteria}, journal = {Federal Register}, volume = {63}, year = {1998}, pages = {68354-68364}, author = {US EPA} } @article {1926, title = {Ambient Water Quality Criteria for copper}, number = {84}, year = {1984}, institution = {Environmental Protection Agency}, address = {Washington, DC}, author = {US EPA} } @article {1840, title = {In depth studies on the health and environmental impacts of selected water pollutants}, year = {1978}, institution = {United States Environment Protection Agency}, author = {US EPA} }