Gama-Rodrigues, Antonio Carlos da, and Antonio Cadima Zevallos. “Effect of Grazing Intensity on the Root System of Pasture”. Pesquisa Agropecuaria Brasileira, vol. 26, no. 3, Mar. 1991, pp. 439-45, doi:10.1590/S1678-3921.pab1991.v26.3360.