1. 1. M. Wichtl, Herbal Drugs, Medpharm Scientific Publishers, Stuttgart, 1994.
2. 2. A.N. Carol, A.A. Linda and J.P. David, Herbal Medicines, The Pharmaceutical Press, London,1996.
3. 3. M. Itoh, N. Asakawa, Y. Hashimoto, M. Ishibashi and H. Miyazaki, J. Pharm. Soc. Jpn., 12, 1150-1154 (1985).
4. 4. S.S. Nina, Pharmaceutical Biomedical Analysis, 5, 289-293 (1987).
5. 5. G. Lu and J. Liu, Yaowu-Fenxi-Zazhi, 8, 137-139 (1988).