1. HPV Challenge Program. http://www.epa.gov/chemrtk/volchall.htm, revision dated 9/18/2001, downloaded 10/18/2001.
2. Letter to Manufacturers/Importers. http://www.epa.gov/opptintr/chemrtk/ceoltr1.htm, revision dated 05/15/2001, downloaded 10/18/2001.
3. Blood on His Hands. http://www.peta.org/liv/animaltimes/a299/gore.html.
4. HPV Chemical Human Health Testing: Animal Welfare Issues and Approaches. http://www.epa.gov/opptintr/chemrtk/humnanml.htm, revision dated 6/14/2001, downloaded 10/19/2001.
5. HPV Challenge Program Chemical List. http://www.epa.gov/chemrtk/hpvchmlt.htm, revision dated 10/15/01, downloaded 10/18/2001.