Singtongratana, N., Vadhanasin, S. and Singkhonrat, J. (2013) “Hydroxychavicol and Eugenol Profiling of Betel Leaves from Piper betle L. Obtained by Liquid-Liquid Extraction and Supercritical Fluid Extraction”, Agriculture and Natural Resources. Bangkok, Thailand, 47(4), pp. 614–623. available at: https://li01.tci-thaijo.org/index.php/anres/article/view/243103 (accessed: 17 September 2026).