Cui L, Liu H, Sun L. Multidisciplinary respiratory rehabilitation in combination with non-invasive positive pressure ventilation in the treatment of elderly patients with severe chronic obstructive pulmonary disease: Treatment of elderly with COPD. Pak J Med Sci [Internet]. 2019Mar.20 [cited 2024Apr.25];35(2). Available from: https://www.pjms.org.pk/index.php/pjms/article/view/459