1. Cidian Z. Dictionary of traditional Chinese medicine. Shanghai: Shanghai Science and Technology Press; 2004.
2. Lee Y-J. The use of bear bile as medicine versus tonic. In: Williamson DF and Phipps MJ, editors. Proceedings of the Third International Symposium on the Trade in Bear Parts. Seoul: TRAFFIC East Asia; 1999. p. 122–126
3. Feng Y, Siu K, Wang N, Ng KM, Tsao SW, Nagamatsu T, et al. Bear bile: dilemma of traditional medicinal use and animal protection. J Ethnobiol Ethnomed. 2009;5:2.
4. Gabriel GG.A bitter medicine: the use of bear bile in China. In: Williamson DF and Phipps MJ, editors. Proceedings of the Third International Symposium on the Trade in Bear Parts. Seoul: TRAFFIC East Asia; 1999. p. 116–120.
5. Hanson DG. Poaching: Oriental demand for undgam and paws decimates California bears. Audubon. 1983;85:127–8.