1. Charles River Pathology Associates, Durham, North Carolina, USA
2. Covance Inc., Madison, Wisconsin, USA
3. National Toxicology Program, National Institute of Environmental Health Sciences and Integrated Laboratory Systems, Research Triangle Park, North Carolina, USA
4. Pfizer, Groton, Connecticut, USA
5. Consultants in Veterinary Pathology, Inc., Murrysville, Pennsylvania, USA
6. Merck KGaA, Darmstadt, Germany
7. The Ohio State University, College of Veterinary Medicine, Columbus, Ohio, USA