Wolff, C., G.H. Haug, A. Timmermann, J.S. Sinninghe Damsté, A. Brauer, D.M. Sigman, M.A. Cane, and D. Verschuren. 2011. “Reduced Interannual Rainfall Variability in East Africa During the Last Ice Age”. Science 333: 743-47. doi:10.1126/science.1203724.