Geise, L., and D. Astúa. “Distribution Extension and Sympatric Occurrence of Gracilinanus Agilis and G. Microtarsus (Didelphimorphia, Didelphidae), With Cytogenetic Notes”. Biota Neotropica, vol. 9, no. 4, Dec. 2009, //www.biotaneotropica.org.br/BN/article/view/587.