Trenberth, K.E., Jones, P.D., and others, 2007
Observations: Surface and Atmospheric Climate Change
Climate Change 2007: The Physical Science Basis. Contribution of the Working Group 1 to the Fourth Assessment Report of the IPCC. Solomon,S., Qin, D., Manning, M., Chen, Z., Marquis, M., Averyt, K.B., Tignor, M. and Miller, H.L. (eds.)]. Cambridge University Press, Cambridge, United Kingdom and New York, NY, USA
Dai, A., Lamb, P.J., Trenberth, K.E., Hulme, M., Jones, P.D. and Xie, P., 2004
The recent Sahel drought is real.
International Journal of Climatology 24, 1323-1331
(keywords: drought Africa climate change)