Chetambath, R., R. A. Kathim, and R. Ibrahim. “Alpha-1-Antitrypsin Level As a Predictor of Acute Exacerbations in Chronic Obstructive Pulmonary Disease: A Prospective Observational Study”. International Journal of Research in Medical Sciences, vol. 12, no. 1, Dec. 2023, pp. 124-8, doi:10.18203/2320-6012.ijrms20233986.