@ARTICLE {OKIKE:2005, title = {Ecological and socio-economic factors affecting agricultural intensification in the West African savannas: evidence from northern Nigeria}, author = {Okike, I. and Jabbar, M. and Manyong, V. and Smith, J. W. }, journal = {Journal of Sustainable Agriculture}, year = {2005}, volume = {27}, number = {2}, pages = {5--37}, issn = {1044-0046}, }