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Frisbie WP, Cho Y, Hummer RA.Frisbie WP, et al. Among authors: hummer ra.Am J Epidemiol. 2001 Feb 15;153(4):372-80. doi: 10.1093/aje/153.4.372.Am J Epidemiol. 2001.PMID: 11207155
Frisbie WP, Echevarria S, Hummer RA.Frisbie WP, et al. Among authors: hummer ra.Matern Child Health J. 2001 Mar;5(1):21-33. doi: 10.1023/a:1011393717603.Matern Child Health J. 2001.PMID: 11341717