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Zhang Y, McConnell R, Gilliland F, Berhane K.Zhang Y, et al.Am J Respir Crit Care Med. 2011 Mar 1;183(5):596-603. doi: 10.1164/rccm.200912-1863OC. Epub 2010 Oct 1.Am J Respir Crit Care Med. 2011.PMID: 20889910Free PMC article.