Qing-Hua, Yan, et al. “Determination of Chlorogenic Acid, Ferulic Acid and Flavonoids in Flos Loniceae by High Performance Liquid Chromatography”. Asian Journal of Chemistry, vol. 23, no. 10, Aug. 2011, pp. 4709-10, https://asianpubs.org/index.php/ajchem/article/view/10961.