Citation Select	Zhou Y, Zhong NS, Li X, Chen S, Zheng J, Zhao D, Yao W, Zhi R, Wei L, He B, Zhang X, Yang C, Li Y, Li F, Du J, Gui J, Hu B, Bai C, Huang P, Chen G, Xu Y, Wang C, Liang B, Li Y, Hu G, Tan H, Ye X, Ma X, Chen Y, Hu X, Tian J, Zhu X, Shi Z, Du X, Li M, Liu S, Yu R, Zhao J, Ma Q, Xie C, Li X, Chen T, Lin Y, Zeng L, Ye C, Ye W, Luo X, Zeng L, Yu S, Guan WJ, Ran P Tiotropium in Early-Stage Chronic Obstructive Pulmonary Disease N Engl J Med. 2017 Sep 07;377(10):923-935
Citation Select	Singh S, Loke YK, Enright PL, Furberg CD Mortality associated with tiotropium mist inhaler in patients with chronic obstructive pulmonary disease: systematic review and meta-analysis of randomised controlled trials BMJ. 2011 Jun 14;342:d3215. doi: 10.1136/bmj.d3215
Citation Select	POET-COPD Investigators, Vogelmeier C, Hederer B, Glaab T, Schmidt H, Rutten-van Mölken MP, Beeh KM, Rabe KF, Fabbri LM Tiotropium versus salmeterol for the prevention of exacerbations of COPD N Engl J Med. 2011 Mar 24;364(12):1093-103
Citation Select	Barr RG, Bourbeau J, Camargo CA, Ram FS Tiotropium for stable chronic obstructive pulmonary disease: A meta-analysis Thorax. 2006 Oct;61(10):854-62. Epub 2006 Jul 14
Citation Select	Salpeter SR, Buckley NS, Salpeter EE Meta-analysis: anticholinergics, but not beta-agonists, reduce severe exacerbations and respiratory mortality in COPD J Gen Intern Med. 2006 Oct;21(10):1011-9
Citation Select	Rodrigo G, Rodrigo C, Burschtin O A meta-analysis of the effects of ipratropium bromide in adults with acute asthma Am J Med. 1999 Oct;107:363-70
Citation Select	Plotnick LH, Ducharme FM Should inhaled anticholinergics be added to 2 agonists for treating acute childhood and adolescent asthma? A systematic review BMJ. 1998 Oct 10;317:971-977