1. Pardey, P. G., Alston, J. M., Christian, J. E. & Fan, S. Summary of a Productive Partnership: The Benefits from U.S. Participation in the CGIAR (International Food Policy Research Institute, Washington DC, 1996).
2. Conway, G.R. The Doubly Green Revolution: Food for All in the 21st Century (Penguin Books, London/Cornell University Press, Ithaca NY, 1999).
3. UNICEF. The State of the World's Children 1998 (Oxford Univ. Press, Oxford/New York, 1998).
4. Somer, A. & West, K.P. Vitamin A Deficiency: Health, Survival and Vision (Oxford Univ. Press, New York and Oxford, 1966).
5. Mann, C.C. Science 283, 310–314 ( 1999).