Echer, Fábio Rafael, and José Eduardo Creste. “Boron Fertilization on Sweet Potato: Effect of Sources, Rates and Application Form”. Semina: Ciências Agrárias, vol. 32, no. 4Sup1, Dec. 2011, pp. 1831-6, doi:10.5433/1679-0359.2011v32n4Sup1p1831.