American Gastroenterological Association
http://www.gastro.org/

International Foundation for Functional Gastrointestinal Disorders
http://www.iffgd.org/

National Institutes of Health (NIH)
http://www.nih.gov/

NIAAA Alcohol and Alcohol Problems Science Database

http://etoh.niaaa.nih.gov

National Cancer Institute
http://www.nci.nih.gov/

Deutsche Gesellschaft für Verdauungs- und Stoffwechselkrankheiten

http://www.dgvs.de/

American Society for Gastrointestinal Endoscopy

http://www.asge.org/

German Association for the Study of Liver Disease

http://www.gasl.de/

American Societey of Clinical Oncology

http://www.asco.org/

Centers for Disease Control and Prevention
http://www.cdc.gov/