Santos, Carlos Antonio Fernandes, et al. “Genetic Variability of Umbu Trees in Brazilian Semi-Arid Region, Based on AFLP Markers”. Pesquisa Agropecuaria Brasileira, vol. 43, no. 8, Oct. 2008, pp. 1037-43, doi:10.1590/S1678-3921.pab2008.v43.234.