Shan, Wen-Jun; Huang, Ling; Zhou, Qi; Jiang, Huai-Lei; Luo, Zong-Hua; Lai, Ke-Fang; Li, Xing-Shu Bioorganic and Medicinal Chemistry Letters, 2012, vol. 22, # 4 p. 1523 - 1526 doi: 10.1016/j.bmcl.2012.01.013