Gruber, D., D. Pohl, S. Vavricka, B. Stutz, M. Fried, and R. Tutuian. “Swiss Tertiary Care Center Experience Challenges the Age- Cohort Effect in Helicobacter Pylori Infection”. Journal of Gastrointestinal and Liver Diseases, vol. 17, no. 4, Dec. 2008, pp. 373-7, https://www.jgld.ro/jgld/index.php/jgld/article/view/2008.4.1.