Improving cereal productivity and farmers' income using a strategic application of fertilizers in West Africa - Tabo, Ramadjita; Bationo, B. André; Gerard, Bruno G.; Ndjeunga, J.; Marchal, D.; Amadou, B.; Annou, G.; Sogodogo, D.; Taonda, J.B.S.; Hassane, O.; Diallo, M.K.; Koala, Saidou (2007)