Original Research

Study design considerations in a large COPD trial comparing effects of tiotropium with salmeterol on exacerbations

Kai-Michael Beeh, Bettina Hederer, Thomas Glaab, Achim Müller, Maureen Rutten-van Moelken, et al

International Journal of Chronic Obstructive Pulmonary Disease 2009, 4:119-125

Published Date: 26 February 2009