Zheng, Dan; Guan, Yuyao; Chen, Xiaozhuo; Xu, Yanpeng; Chen, Xiaoguang; Lei, Pingsheng Bioorganic and Medicinal Chemistry Letters, 2011, vol. 21, # 11 p. 3257 - 3260 doi: 10.1016/j.bmcl.2011.04.030