Gregson, Stephen J.; Howard, Philip W.; Barcella, Simona; Nakamya, Anthonia; Jenkins, Terence C.; Kelland, Lloyd R.; Thurston, David E. Bioorganic and Medicinal Chemistry Letters, 2000, vol. 10, # 16 p. 1849 - 1851 doi: 10.1016/S0960-894X(00)00350-4