Radhitya, A. F., and D. Zairus. “CHRONIC OBSTRUCTIVE PULMONARY DISEASE EXACERBATION”. Jurnal Kesehatan Dan Agromedicine, vol. 1, no. 1, Aug. 2014, pp. 49-54, https://juke.kedokteran.unila.ac.id/index.php/agro/article/view/1335.