1. Helicobacter pylori-negative duodenal ulcer;Borody;Am J Gastroenterol,1991
2. Helicobacter pylori-negative duodenal ulcer;Nensey;Am J Gastroenterol,1991
3. Helicobacter pylori associated chronic gastritis and peptic ulceration in patients taking non-steroidal anti-inflammatory drugs;Shallcross;Aliment Pharmacol Ther,1990
4. Helicobacter pylori-negative gastric ulcer;Borody;Am J Gastroenterol,1992
5. Nonsteroidal antünflammatory drug-associated gastric ulcers do not require Helicobacter pylori for their development;Laine;Am J Gastroenterol,1992