@book{78517,
	author = {Heisey, Paul W. and Mwangi, Wilfred.},
	title = {Fertilizer use and maize production in Sub-Saharan Africa},
	publisher = {Centro Internacional de Mejoramiento de Maíz y Trigo,},
	year = {1996.},
	series = {Economics. Working paper},
	address = {México, D.F. :}
}