Song, Shao-Xing; Wu, Ming-Li; He, Xiao-Peng; Zhou, Yu-Bo; Sheng, Li; Li, Jia; Chen, Guo-Rong Bioorganic and Medicinal Chemistry Letters, 2012, vol. 22, # 5 p. 2030 - 2032 doi: 10.1016/j.bmcl.2012.01.069