1. Eurordis.European Organisation for Rare Diseases. What is a rare disease?Available at:http://www.eurordis.org/article.php3?id_article=252(accessed May 2006).
2. National Organization for Rare Disorders.About NORD. Available at:http://www.rarediseases.org/info/about.html(accessed May 2006).
3. National Institutes of Health.Office of Rare Diseases. About ORD. Available at:http://ord.aspensys.com/html/resources/about_ord.html(accessed May 2006).
4. Eurordis.Rare diseases in numbers. Preliminary report from an on going bibliographic study initiated by Eurordis in partnership with Orphanet. Available at:http://www.orpha.net/actor/Orphanews/2005/doc/Rare_Diseases_in_Numbers.pdf(accessed May 2006).