Paiva, Élder Antônio Sousa e, et al. “Occurrence and Structure of Extrafloral Nectaries in Pterodon Pubescens Benth. And Pterodon Polygalaeflorus Benth”. Pesquisa Agropecuaria Brasileira, vol. 36, no. 2, Feb. 2001, pp. 219-24, https://doi.org/10.1590/S1678-3921.pab2001.v36.6130.