@ARTICLE {OKOGUN:2004, title = {Soybean yield determinants and response to rhizobial inoculation in an on-farm trial in the northern Guinea savanna of Nigeria}, author = {Okogun, J. and Otuyemi, B. and Sanginga, P. }, journal = {West African Journal of Applied Ecology}, year = {2004}, volume = {6}, pages = {30--39}, }