OPUS Study: Effect of Roflumilast on Exacerbation Rate in Patients With Chronic Obstructive Pulmonary Disease (BY217/M2-111) [clinicaltrials:NCT00076089]

OPUS Study: Effect of Roflumilast on Exacerbation Rate in Patients With Chronic Obstructive Pulmonary Disease (BY217/M2-111) [clinicaltrials:NCT00076089]