Aroonrerk, N., and N. Kamkaen. “Anti-Inflammatory Activity of Quercus Infectoria, Glycyrrhiza Uralensis, Kaempferia Galanga and Coptis Chinensis, the Main Components of Thai Herbal Remedies for Aphthous Ulcer”. Journal of Health Research, vol. 23, no. 1, Nov. 2018, pp. 17-22, https://he01.tci-thaijo.org/index.php/jhealthres/article/view/156318.