Villalobos, F., A. A. Valerio, and A. P. Retana. “A Phylogeny of Howler Monkeys (Cebidae: <i>Alouatta</i≫) Based on Mitochondrial, Chromosomal and Morphological Data”. Revista De Biología Tropical, vol. 52, no. 3, Sept. 2004, pp. 665–677, https://revistas.ucr.ac.cr/index.php/rbt/article/view/15354.