de Sá, Nadja M. Horta, Ivanildo Evódio Marriel, and Avílio A. Franco. 1994. “Variability in Individual Nodule Activity of Single Strains of <i>Rhizobium etli< i> and R. <i>tropici in< i> Symbiosis With <i>Phaseolus vulgaris< I>”;. Pesquisa Agropecuaria Brasileira 29 (12):1897-1904. https://doi.org/10.1590/S1678-3921.pab1994.v29.4247.