Machado, Walter Coutinho, and Johanna Döbereiner. “Further Studies on the Physiology of <i>Azotobacter paspali< i> and Its Dependence on the Plant (<i>Paspalum notatum< I>)”. Pesquisa Agropecuaria Brasileira, vol. 4, no. 1, Apr. 2014, pp. 53-58, doi:10.1590/S1678-3921.pab1969.v4.17777.