Ambouta, Karimou Jean-Marie, Issaka Amadou, and Issa Souley. 1998. “Soil Fertility Changes and Management in Gakudi (Maradi, Niger)”. Cahiers Agricultures 7 (5):395-400 (1). https://revues.cirad.fr/index.php/cahiers-agricultures/article/view/30115.