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Author/Creator
- Geological Survey (U.S.)26
- United States. Environmental Protection Agency. Office of Air Quality Planning and Standards20
- United States. Environmental Protection Agency16
- National Water-Quality Assessment Program (U.S.)6
- United States6
- National Institute for Occupational Safety and Health5
- United States. Forest Service5
- United States. Environmental Protection Agency. Office of Research and Development4
- Bennett, Claude F.3
- League of Nations3
- League of Nations. Communications and Transit Organization3
- Marshall, Mary G. (Mary Gladys)3
- United States. Agricultural Research Service3
- United States. Coast Guard3
- United States. Cooperative State Research, Education, and Extension Service3
- United States. Environmental Protection Agency. Emission Standards Division3
- United States. Environmental Protection Agency. Office of Pollution Prevention and Toxics3
- United States. Environmental Protection Agency. Office of Solid Waste and Emergency Response3
- United States. General Accounting Office3
- Center for Environmental Research Information (U.S.)2