1. National Toxicology Program, National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, North Carolina, USA
2. Charles River Laboratories, Inc., Durham, North Carolina, USA
3. Integrated Laboratory Systems, Inc., Research Triangle Park, North Carolina, USA
4. Boehringer Ingelheim Pharma GmbH & Co. KG, Ingelheim, Germany
5. Experimental Pathology Laboratories, Inc., Research Triangle Park, North Carolina, USA
6. Experimental Pathology Laboratories, Inc., Sterling, Virginia, USA