Gupta, Rajiv, and Sfurti Mann. “Correlation Between COPD And Echocardiographic Features With Severity Of Disease: Correlation Between COPD And Echocardiographic Features With Severity Of Disease”. National Journal of Integrated Research in Medicine 7, no. 1 (January 17, 2018): 26–30. Accessed November 22, 2024. https://nicpd.ac.in/ojs-/index.php/njirm/article/view/1038.