Sofia, Sefri N., et al. “Role of Phosphodiesterase-3 Inhibitor in Cardiorespiratory Fitness and Functional Class of Patients With Pulmonary Hypertension: A Randomized, Double-Blind, Placebo-Controlled Trial”. Narra J, vol. 5, no. 1, Jan. 2025, p. e1301, doi:10.52225/narra.v5i1.1301.