useful link

• American Association For The Study Of Liver Diseases
   
• American Gastroenterological Association
   
• Digestive Disease Week 2007
   
• Doctor's Guide 
   
• International Agency for Research on Cancer 
   
• International Society For Infectious Diseases
   
• International Union Against Cancer
   
• Iranian Association of Gastroentrology and Hepatology
   
• IranMedex
   
• Medical Council Organization
   
• Ministry Of Health and Medical Education
   
• National Cancer Institute
   
• Research Center for Gastroentrology & Liver Diseases
   
• Scientiifc Information Database
   
• Tehran University of Medical Sciences
   
• The European Association For The Study Of The Liver 
   
• United European Gastroentrology Week
   
• World Gastroenterology Organisation