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Gordon JR, Swystun VA, Li F, Zhang X, Davis BE, Hull P, Cockcroft DW.Gordon JR, et al. Among authors: cockcroft dw.Eur Respir J. 2003 Jul;22(1):118-26. doi: 10.1183/09031936.03.00031102.Eur Respir J. 2003.PMID: 12882461Free article.Clinical Trial.