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Kunisaki KM, Niewoehner DE, Connett JE; COPD Clinical Research Network.Kunisaki KM, et al.Am J Respir Crit Care Med. 2012 Feb 1;185(3):286-90. doi: 10.1164/rccm.201109-1644OC. Epub 2011 Nov 10.Am J Respir Crit Care Med. 2012.PMID: 22077070Free PMC article.Clinical Trial.