12 Week Comparison of 5 Mcg and 10 Mcg of Tiotropium / Respimat, Placebo and Ipratropium MDI in COPD [clinicaltrials:NCT00239473]

12 Week Comparison of 5 Mcg and 10 Mcg of Tiotropium / Respimat, Placebo and Ipratropium MDI in COPD [clinicaltrials:NCT00239473]