H. P. Haag and J. Orlando Filho, “ Varietal and soil influence on nutritional status of sugarcane (Saccharum spp) as determined by foliar analysis ”, An. Esc. Super. Agr. Luiz de Queiroz, vol. 33, pp. 105–147, Jan. 1976, doi: 10.1590/S0071-12761976000100010.