[1] Lyer SS. Drug News Perspect, 1991, 4: 228. [2] Majumdar N, Datta J K. Indian J Exp Biol, 1990, 28: 717. [3] Ray S, Grover Pk, Anand N. Indian J Chem, 1971, 9: 727. [4] U. S. Patent 3, 822, 287 (1974). [5] Ji XS, Yan J F, Wang XF. Chin J Pharm, 1996, 27: 133. [6] Ji XS, Wang XF. J Chin Mass Spectro Soc, 1996, 17: 45. [7] Ji XS, Yan J F. Chin J Mag Res, 1997, 14: 187.