Rampengan, Starry H, Joedo Prihartono, Minarma Siagian, and Suzanna Immanuel. 2015. “The Effect of Enhanced External Counterpulsation Therapy and Improvement of Functional Capacity in Chronic Heart Failure Patients: A Randomized Clinical Trial”. Acta Medica Indonesiana 47 (4). https://www.actamedindones.org/index.php/ijim/article/view/18.