Shanmuganathan, Aruna, Advita G., Meenakshi N., Ragulan R., Nisha Ganga, and Pukazhenthi K. “Correlation of Grade of Pulmonary Artery Pressure With Six Minutes Walk Distance and Dyspnoea Grading in Group 3 Pulmonary Artery Hypertension”. International Journal of Advances in Medicine 5, no. 2 (March 21, 2018): 343–350. Accessed December 24, 2025. https://www.ijmedicine.com/index.php/ijam/article/view/1028.