Zhang C- hong, Liu J- hua, Zhao J- qing, Zhang Z- hua, Gu X. Clinical Study on the effect of Bi-level Positive Airway Pressure Therapy on COPD complicated with Anxiety and Depression. Pak J Med Sci [Internet]. 2023Aug.3 [cited 2024May20];39(5). Available from: https://pjms.org.pk/index.php/pjms/article/view/7259