de Faria, Clementino M. B, and José Ribamar Pereira. “Sources and Levels of Nitrogen and Onion Yield in the Submedio São Francisco Region”. Pesquisa Agropecuaria Brasileira, vol. 27, no. 3, Mar. 1992, pp. 403-7, doi:10.1590/S1678-3921.pab1992.v27.3662.