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Zhang X, Luo H, Gregg EW, Mukhtar Q, Rivera M, Barker L, Albright A.Zhang X, et al. Among authors: gregg ew.Am J Public Health. 2010 Aug;100(8):1434-41. doi: 10.2105/AJPH.2009.168831. Epub 2010 Jun 17.Am J Public Health. 2010.PMID: 20558810Free PMC article.