“Correlation of Hospital Anxiety and Depression Scale (HADS) and Six Minute Walk Test (6MWT) Performance in Chronic Obstructive Pulmonary Disease (COPD) Patients”., Int Jour of Biomed Res, vol. 11, no. 6, p. e5419, Aug. 2020, Accessed: Mar. 13, 2025. [Online]. Available: https://ssjournals.co.in/index.php/ijbr/article/view/5419