Hardoko, Hardoko, Marcella Jessica, and Yuniwaty Halim. 2020. “Antibacterial Activity of Cough Suppressant Functional Drink from Betel Leaves (Piper sarmentosum), Lime (Citrus Aurantifolia) and Honey: doi.org 10.26538 Tjnpr V4i10.7”. Tropical Journal of Natural Product Research (TJNPR) 4 (10):695-702. https://www.tjnpr.org/index.php/home/article/view/1023.