The Interagency Coordinating Committee on the Validation of Alternative Methods (ICCVAM) - The National Toxicology
Programme (NTP) at the National Institute of Environmental Health Sciences (NIEHS): http://iccvam.niehs.nih.gov/
PubMed - A service of the National Library of Medicine, includes over 14 million citations for biomedical articles
dating back to the 1950s: http://www.ncbi.nlm.nih.gov/entrez/query.fcgi