Wen, Xiaoan, Sun, Hongbin, Liu, Jun, Cheng, Keguang, Zhang, Pu, Zhang, Liying, Hao, Jia, Zhang, Luyong, Ni, Peizhou et al (2008) Naturally Occurring Pentacyclic Triterpenes as Inhibitors of Glycogen Phosphorylase: Synthesis, Structure−Activity Relationships, and X-ray Crystallographic Studies†. Journal of Medicinal Chemistry, 51 (12). pp. 3540-3554. ISSN 0022-2623