Souto, Sebastião M., and Johanna Döbereiner. 2014. “Methodology for Measuring N2 Fixation in Detached Roots of Tropical Forage Grasses”. Pesquisa Agropecuaria Brasileira 19 (5):553-65. https://doi.org/10.1590/S1678-3921.pab1984.v19.15599.