Ferreira, Evander Alves, et al. “Micromorphological Characteristics of Barnyardgrass Biotypes Resistant and Susceptible to Quinclorac”. Pesquisa Agropecuaria Brasileira, vol. 47, no. 8, Sept. 2012, pp. 1048-56, doi:10.1590/S1678-3921.pab2012.v47.12513.