@INBOOK {JUO:1992, title = {Mixed root-crop systems in wet sub-Saharan Africa}, author = {Juo, A. S. R. and Ezumah, H. C. }, editor = {Pearson, C. J. }, year = {1992}, type = {Ecosystems of the world: field crops ecosystems}, pages = {243--258}, publisher = {Elsevier}, address = {Amsterdam, the Netherlands}, }