Cook, Gregory R.; Manivannan, Ethirajan; Underdahl, Thane; Lukacova, Viera; Zhang, Yufen; Balaz, Stefan Bioorganic and Medicinal Chemistry Letters, 2004, vol. 14, # 19 p. 4935 - 4939 doi: 10.1016/j.bmcl.2004.07.023