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Fogarty AW, Jones S, Britton JR, Lewis SA, McKeever TM.Fogarty AW, et al.Thorax. 2007 Jun;62(6):515-20. doi: 10.1136/thx.2006.066969. Epub 2007 Jan 24.Thorax. 2007.PMID: 17251312Free PMC article.