Kang, Yong Koo; Shin, Kye Jung; Yoo, Kyung Ho; Seo, Kyung Jae; Park, Seung Yong; Kim, Dong Jin; Park, Sang Woo Bioorganic and Medicinal Chemistry Letters, 1999, vol. 9, # 16 p. 2385 - 2390 doi: 10.1016/S0960-894X(99)00407-2