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Sverrild A, Malinovschi A, Porsbjerg C, Backer V, Alving K.Sverrild A, et al. Among authors: porsbjerg c.Respir Med. 2013 Jan;107(1):150-2. doi: 10.1016/j.rmed.2012.09.004. Epub 2012 Nov 21.Respir Med. 2013.PMID: 23177390Free article.