LABA/LAMA combination in COPD: a meta-analysis on the duration of treatment
Luigino Calzetta, Paola Rogliani, Josuel Ora, Ermanno Puxeddu, Mario Cazzola, Maria Gabriella Matera
European Respiratory Review Mar 2017, 26 (143) 160043; DOI: 10.1183/16000617.0043-2016