Ambouta, K. J.-M. ., I. Amadou, and I. Souley. “Soil Fertility Changes and Management in Gakudi (Maradi, Niger)”. Cahiers Agricultures, vol. 7, no. 5, Sept. 1998, pp. 395-400 (1), https://revues.cirad.fr/index.php/cahiers-agricultures/article/view/30115.