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Drake, N. and Blench, R.M. and Armitage, S.J. and Bristow, Charlie S. and White, K.H. (2011) Ancient watercourses and biogeography of the Sahara explain the peopling of the desert. Proceedings of the National Academy of Sciences of the United States of America 108 (2), pp. 458-462. ISSN 0027-8424.