N. Ng’ang’a, J., & P. Msumali, G. (2005). Effects of carbamate and pyrethroid insecticides on cowpea bradyrhizobial population assessed in sand culture and on nitrogen fixation in soil. Uganda Journal of Agricultural Sciences, 11(1), 9–13. Retrieved from http://journal.naro.go.ug/index.php/ujas/article/view/315