Chao, Yu-Hua; Kuo, Sheng-Chu; Ku, Kelvin; Chiu, I-Ping; Wu, Chun-Hsiung; Mauger, Anthony; Wang, Hui-Kang; Lee, Kuo-Hsiung Bioorganic and Medicinal Chemistry, 1999 , vol. 7, # 6 p. 1025 - 1031