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Davis MS, Freed AN.Davis MS, et al. Among authors: freed an.Eur Respir J. 1999 Jul;14(1):57-62. doi: 10.1034/j.1399-3003.1999.14a11.x.Eur Respir J. 1999.PMID: 10489829Free article.
Freed AN, Omori C, Hubbard WC, Adkinson NF Jr.Freed AN, et al.Eur Respir J. 1994 Jul;7(7):1308-16. doi: 10.1183/09031936.94.07071308.Eur Respir J. 1994.PMID: 7925912Free article.