J. Édson Zilli, L. C. Marson, B. F. Marson, V. Gianluppi, R. J. Campo, and M. Hungria, “Soybean inoculation by spraying <i>Bradyrhizobium</i> over plants”, PAB, vol. 43, no. 4, pp. 541–544, Aug. 2008.