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Witt WP, Wisk LE, Cheng ER, Hampton JM, Hagen EW.Witt WP, et al. Among authors: hagen ew.Matern Child Health J. 2012 Oct;16(7):1525-41. doi: 10.1007/s10995-011-0916-4.Matern Child Health J. 2012.PMID: 22124801Free PMC article.