title: Expression of concern: Bombardier et al., "Comparison of upper gastrointestinal toxicity of rofecoxib and naproxen in patients with rheumatoid arthritis," N Engl J Med 2000;343:1520-8.
authors.forename: Gregory D
authors.initials: GD
authors.lastname: Curfman
authors.forename: Stephen
authors.initials: S
authors.lastname: Morrissey
authors.forename: Jeffrey M
authors.initials: JM
authors.lastname: Drazen