1. National Center for Environmental Assessment, Office of Research and Development (ORD), U.S. Environmental Protection Agency (EPA), Research Triangle Park, North Carolina, USA
2. University of California Los Angeles Institute for Society and Genetics, Los Angeles, California, USA
3. National Health and Environmental Effects Research Laboratory, ORD, U.S. EPA, Research Triangle Park, North Carolina, USA
4. Division of Extramural Research and Training, National Institute of Environmental Health Sciences, National Institutes of Health, Department of Health and Human Services, Research Triangle Park, North Carolina, USA