Pinckney R, O’Brien R, Piccirillo J, Littenberg B. Evaluation of co-morbidity indices in patients admitted for Chronic Obstructive Pulmonary Disease. Monaldi Arch Chest Dis [Internet]. 2004 Dec. 30 [cited 2024 Nov. 22];61(4). Available from: https://www.monaldi-archives.org/macd/article/view/683