Preparative isolation and purification of coumarins from Cnidium monnieri (L.) Cusson by high-speed counter-current chromatography Liu RenMin; Feng Lei; Sun AiLing; Kong LingYi Journal of Chromatography, A 1055(1/2): 71-76 2004 https://eurekamag.com/research/004/280/004280102.php