1. Prevalence of helicobacter pylori at oral and gastrointestinal sites in children: evidence for possible oral-to-oral transmission;Allaker;J. Med. Microbiol.,2002
2. Prevalence of Helicobacter (formerly Campylobacter) pylori infection in Saudia Arabia, and comparison of those with and without upper gastrointestinal symptoms;al-Moagel;Am. J. Gastroenterol.,1990
3. Helicobacter Pylori [Text];Araujo Boira,2015
4. Relationship of Helicobacter pylori to serum pepsinogens in an asymptomatic Japanese population;Asaka;Gastroenterology,1992
5. Contaminated water as a source of Helicobacter pylori infection: a review;Aziz;J. Adv. Res.,2015