Chen, L. et al. 2013. Inhibitory Effect of Extract from Twelve Chinese Medical Herbs and Two Active Quaternary Protoberberine Alkaloid from Coptis chinensis Franch. Asian Journal of Chemistry. 25, 17 (Nov. 2013), 9667–9671. DOI:https://doi.org/10.14233/ajchem.2013.15125.