Fleck, Nilson Gilberto, and Paulo Régis F. da Silva. 2014. “Effects of Timing of Nitrogen Side-Dressing Application in Sunflower With and Without Weed Control”. Pesquisa Agropecuaria Brasileira 24 (6):669-76. https://doi.org/10.1590/S1678-3921.pab1989.v24.15864.