Dr. Nitin Kumar, D. K. L. , D. P. S. , D. N. K. ,. “To Study the Role of Bosentan in Patients With Irreversible Obstructive Pulmonary Disease Having Mild to Moderate Pulmonary Arterial Hypertension”. International Journal of Medical Science and Clinical Invention, vol. 4, no. 5, May 2017, doi:10.18535/ijmsci/v4i5.03.