He, Qiu-Qin; Gu, Shuang-Xi; Liu, Jia; Wu, Hai-Qiu; Zhang, Xuan; Yang, Liu-Meng; Zheng, Yong-Tang; Chen, Fen-Er Bioorganic and Medicinal Chemistry, 2011, vol. 19, # 16 p. 5039 - 5045 doi: 10.1016/j.bmc.2011.06.020