Fatima, Nazia, et al. “COMPARISON OF THE EFFICACY OF SILDENAFIL ALONE VERSUS SILDENAFIL PLUS BOSENTAN IN NEWBORNS WITH PERSISTENT PULMONARY HYPERTENSION”. Journal of Ayub Medical College Abbottabad, vol. 30, no. 3, June 2018, pp. 333-6, https://www.jamc.ayubmed.edu.pk/index.php/jamc/article/view/2954.