1. Ho TN, Liu SW (2001) A worldwide monograph of Gentiana. Science Press, Beijing, pp 174–175
2. Yang YC (ed) (1991) North-western plateau institute of biology. Qinghai People Press, Xining, p 11
3. The State Pharmacopoeia Commission of People’s Republic of China, Vol.1 (2005) Chemical Industry Press, Beijing, China, p 210
4. Yang J, Ma J, Zhou DX, He L (2006) Chin Trad Herb Drugs 37(2):187–189
5. Bailleul F, Leveau AM, Durand M (1981) J Nat Prod 44(5):573–575