Author/Creator
- National Center for Education Statistics55
- Educational Testing Service46
- O'Sullivan, Christine Y.46
- United States. National Aeronautics and Space Administration. Scientific and Technical Information Branch25
- United States. Environmental Protection Agency. Office of Solid Waste and Emergency Response22
- Langley Research Center18
- United States. Environmental Protection Agency. Office of Air Quality Planning and Standards18
- United States. National Aeronautics and Space Administration18
- United States. Environmental Protection Agency17
- International Labour Office15
- United States. Agency for Health Care Policy and Research13
- Economist Intelligence Unit (Great Britain)11
- National Institute of Standards and Technology (U.S.)11
- National Science Foundation (U.S.). Division of Science Resources Studies10
- United States. Environmental Protection Agency. Technology Innovation Office9
- United States. National Park Service8
- United States. Department of Agriculture. Economic Research Service7
- United States. Environmental Protection Agency. Chemical Emergency Preparedness and Prevention Office7
- United States. Forest Service7
- Geological Survey (U.S.)6