Dillasamola, Dwisari, et al. “Stigmasterol Isolated from Sungkai (Peronema Canescens Jack) Leaves Induced Natural Killer Cells in SARS-CoV-2 Antigen Challenged Albino Mice: Http: www.doi.org 10.26538 Tjnpr V7i12.8”. Tropical Journal of Natural Product Research (TJNPR), vol. 7, no. 12, Dec. 2023, pp. 5420-3, https://tjnpr.org/index.php/home/article/view/3159.