1. M. Yoshihiro, K. Minpei, and O. Yuusuke, et al., Nat. Prod. Lett., 14, 357 (1999).
2. Dequan Yu and Junshan Yang, Nuclear Magnetic Resonance Spectrum of Analytical Chemistry Manual (volume 7) 2nd ed., Chemical Industry Publishers, Beijing, 1999, 901pp.
3. Yun Huang, Qiang Wang, and Wencai Ye, Chin. J. Nat. Med., 3, 138 (2005).
4. Yun Huang, Lijian Cui, and Qiang Wang, Acta Pharm. Sin., 41, 361 (2006).
5. Huang Yun, Cui Lijian, and Wang Qiang, China J. Chin. Mater. Med., 31, 1230 (2006).