@ARTICLE {SANGINGA:1996b, title = {Nodulation and estimation of symbiotic nitrogen fixation by herbaceous and shrub legumes in Guinea Savanna in Nigeria}, author = {Sanginga, N. and Wirkam, L. E. and Okogun, J. }, journal = {Biology and Fertility of Soils}, year = {1996}, volume = {23}, pages = {441--448}, }