TY - JOUR T1 - Four-year trial of tiotropium in chronic obstructive pulmonary disease JF - Canadian Family Physician JO - Can Fam Physician SP - 848 LP - 849 VL - 58 IS - 8 AU - Anthony D. D’Urzo AU - Pieter Jugovic AU - Reuven Jhirad AU - Jacques Bouchard Y1 - 2012/08/01 UR - http://www.cfp.ca/content/58/8/848.abstract N2 - ER -