Zhu, Hong, et al. “Simultaneous Quantitation of Eight Coumarins in Radix Angelicae Dahuricae by Micellar Electrokinetic Capillary Chromatography”. Asian Journal of Chemistry, vol. 23, no. 9, June 2011, pp. 3893-7, https://asianpubs.org/index.php/ajchem/article/view/10754.