Nepomuceno, A.L. and da Silva, P.R. ferreira 1992. Effect of plant arrangement and weed competition on plant traits related to sunflower harvesting. Pesquisa Agropecuaria Brasileira. 27, 7 (Jul. 1992), 1057–1063. DOI:https://doi.org/10.1590/S1678-3921.pab1992.v27.3742.