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Chung KF, Lammers JW, McCusker M, Roberts NM, Nichol GM, Barnes PJ.Chung KF, et al.Eur Respir J. 1989 Sep;2(8):763-8.Eur Respir J. 1989.PMID: 2680584Clinical Trial.
Hsu JY, Stone RA, Logan-Sinclair RB, Worsdell M, Busst CM, Chung KF.Hsu JY, et al. Among authors: chung kf.Eur Respir J. 1994 Jul;7(7):1246-53. doi: 10.1183/09031936.94.07071246.Eur Respir J. 1994.PMID: 7925902Free article.