Zhang, Q; Cai, L; Zhong, G; Luo, W (2010). "Simultaneous determination of jatrorrhizine, palmatine, berberine, and obacunone in Phellodendri Amurensis Cortex by RP-HPLC". Zhongguo Zhong yao za zhi = Zhongguo zhongyao zazhi = China journal of Chinese materia medica35 (16): 2061–4. PMID21046728.