1. Office of Environmental Health Hazard Assessment, California Environmental Protection Agency, Oakland, California, USA
2. Pediatric Environmental Health Specialty Unit, University of California at San Francisco, San Francisco, California, USA
3. National Health and Environmental Effects Laboratory, Office of Research and Development, U.S. Environmental Protection Agency, Research Triangle Park, North Carolina, USA
4. Maine Center for Disease Control, Augusta, Maine, USA
5. Biology Department, Morrill Science Center, University of Massachusetts at Amherst, Amherst, Massachusetts, USA