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Evans RA, Singh SJ, Collier R, Williams JE, Morgan MD.Evans RA, et al. Among authors: singh sj.Respir Med. 2009 Jul;103(7):1070-5. doi: 10.1016/j.rmed.2009.01.009. Epub 2009 Feb 13.Respir Med. 2009.PMID: 19217765Free article.