Wyatt, Paul G; Coomber, Barry A; Evans, Derek N; Jack, Torquil I; Fulton, Heather E; Wonacott, Alan J; Colman, Peter; Varghese, Jose Bioorganic and Medicinal Chemistry Letters, 2001, vol. 11, # 5 p. 669 - 673 doi: 10.1016/S0960-894X(01)00019-1