Chern, Jyh-Haur; Shia, Kak-Shan; Hsu, Tsu-An; Tai, Chia-Liang; Lee, Chung-Chi; Lee, Yen-Chun; Chang, Chih-Shiang; Tseng, Sung-Nien; Shih, Shin-Ru Bioorganic and Medicinal Chemistry Letters, 2004 , vol. 14, # 10 p. 2519 - 2525