Saccol, A.V. et al. (1993) “Competition of barnyardgrass on soybean cultivated in a hydromorphic soil. I. effect on weed dry matter production and soybean grain yield”, Pesquisa Agropecuaria Brasileira, 28(7), pp. 803–812. doi:10.1590/S1678-3921.pab1993.v28.3941.