Fukui, Hideto; Tsuchiya, Yoshinori; Fujita, Keiko; Nakagawa, Tadakiyo; Koshino, Hiroyuki; Nakata, Tadashi Bioorganic and Medicinal Chemistry Letters, 1997, vol. 7, # 16 p. 2081 - 2086 doi: 10.1016/S0960-894X(97)00365-X