Tripp, R., Walker, D.J., Opoku-Apau, A., Dankyi, A.A. and Delimini, L.L. (1998) Seed management by small-scale farmers in Ghana. A study of maize and cowpea seed in the Brong-Ahafo and Volta regions (NRI Bulletin 68). [Working Paper]

Tripp, R., Walker, D.J., Miti, F., Mukumbuta, S. and Zulu, M.S. (1998) Seed management by small-scale farmers in Zambia. A study of cowpea, groundnut and sorghum seed in the Southern and Western Provinces (NRI Bulletin 76). [Working Paper]