Siow Ping, T., Nafiah, M. A., Yean Shan, L., Awang, K., & Ahmad, K. (2013). Isolation of Stigmasterol from the Bark of Kopsia singapurensis Ridl. Journal of Science and Mathematics Letters, 5(1), 28-34. https://ejournal.upsi.edu.my/index.php/JSML/article/view/351