Edra, A., A. Syamsu, and D. . Siswanti. “Severity of Obstruction Associated With Pulmonary Hypertension in COPD Patients at Arifin Achmad General Hospital: What Factors Influence? ”. Respiratory Science, vol. 5, no. 3, June 2025, pp. 185-97, doi:10.36497/respirsci.v5i3.173.