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al-Roomi KA, Dobson AJ, Hall E, Heller RF, Magnus P.al-Roomi KA, et al. Among authors: heller rf.Am J Epidemiol. 1989 Mar;129(3):503-10. doi: 10.1093/oxfordjournals.aje.a115161.Am J Epidemiol. 1989.PMID: 2916543