Serpa, Aryno, and Helvécio De-Polli. 2014. “Genetic Variation in Centrosema-Rhizobium Symbiosis”. Pesquisa Agropecuaria Brasileira 11 (5): 29-32. https://doi.org/10.1590/S1678-3921.pab1976.v11.16885.