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Simon JA, Schreiber GB, Crawford PB, Frederick MM, Sabry ZI.Simon JA, et al. Among authors: sabry zi.Public Health Rep. 1993 Nov-Dec;108(6):760-4.Public Health Rep. 1993.PMID: 8265761Free PMC article.
Simon JA, Schreiber GB, Crawford PB, Frederick MM, Sabry ZI.Simon JA, et al. Among authors: sabry zi.Epidemiology. 1993 Nov;4(6):537-42. doi: 10.1097/00001648-199311000-00010.Epidemiology. 1993.PMID: 8268283