Field evaluation of cassava varieties under drought stress in Kenya, Tanzania and Ghana - Mutegi, R.; Ferguson, Morag E.; Maass, Brigitte L.; Tiessen, H.; Mkamilo, G.S.; Kamau, J.; Adjebeng-Danquah, J.; Alves, A.A.C.; Setter, Tim L.; Fregene, Martin A. (Empresa Brasileira de Pesquisa Agropecuária, 2008)