Costa, Nivaldo Duarte, et al. “Nitrogen Levels through Fertirrigation and Plant Density on Melon Crop in a Vertisol”. Pesquisa Agropecuaria Brasileira, vol. 35, no. 3, Mar. 2000, pp. 491-5, doi:10.1590/S1678-3921.pab2000.v35.5813.