Bangash, M. M. H., Zaidi, S. B. H., Zaidi, S. M. A., & Khan, I. (2010). USE OF SPIROMETRY IN DETECTING AIRWAY OBSTRUCTION IN ASYMPTOMATIC SMOKERS: Spirometry in Asymptomatic Smokers. Pakistan Armed Forces Medical Journal, 60(3), 368-72. https://pafmj.org/PAFMJ/article/view/1332