It seems that four primary studies were included:
(1) a meta-analysis (efficacy ofantibiotics in eliminating H pylori)
(2) an efficacy and side-effect study of triple drug regimens in eliminating H pylori
(3) a curative study of duodenal ulcers after H pylori elimination
and (4) an RCT analysis of amoxicillin with omeprazole versus triple therapy for H pylori elimination in duodenal ulcer disease.