citation
Manyong, V., Makinde, K.O. & Ogungbile, A.G.O. (2001). Agricultural transformation and fertilizer use in the cerealbased systems of the northern Guinea savanna. In B. Vanlauwe, J. Diels, N. Sanginga and R. Merckk, Integrated plant nutrient management in Sub-Saharan Africa: from concept to practice. Ibadan, Nigeria: IITA. (p. 75-86).