Díaz, M.I.H. et al. 2008. Nitrogen levels and their fractioning in gladiolus cultivation for Ferralitic Red soils. Pesquisa Agropecuaria Brasileira. 43, 1 (Jan. 2008), 21–27. DOI:https://doi.org/10.1590/S1678-3921.pab2008.v43.7956.