Hossain, M. A., Z. Zakaria, and Z. Ismaila. “Quantitative Determination of Sinensetin in Orthosiphon Stamineus Leaves by Thin-Layer Chromatography and Imaging Densitometry: Short Communication”. Biological Sciences - PJSIR, vol. 48, no. 2, Apr. 2005, pp. 108-9, https://v2.pjsir.org/index.php/biological-sciences/article/view/1351.