Silva, Valéria Nogueira da, et al. “CHARACTERIZATION AND SELECTION OF NATIVE POPULATIONS OF SOIL RHIZOBIA OF THE SEMI-ARID REGION OF PERNAMBUCO, BRAZIL”. Pesquisa Agropecuária Tropical [Agricultural Research in the Tropics], vol. 37, no. 1, Oct. 2007, pp. 16-21, https://revistas.ufg.br/pat/article/view/1841.