Kuduk, Scott D.; Zheng, Fuzhong F.; Sepp-Lorenzino, Laura; Rosen, Neal; Danishefsky, Samuel J. Bioorganic and Medicinal Chemistry Letters, 1999, vol. 9, # 9 p. 1233 - 1238 doi: 10.1016/S0960-894X(99)00185-7