Shin, Kye Jung; Koo, Ki Dong; Yoo, Kyung Ho; Kang, Yong Koo; Park, Sang Woo; Kim, Dong Jin Bioorganic and Medicinal Chemistry Letters, 2001, vol. 11, # 17 p. 2397 - 2399 doi: 10.1016/S0960-894X(01)00451-6