Wujek, D. E., and J. M. Cocuzza. “Morphology of Hair of Two-and Three-Toed Sloths (Edentata: Bradypodidae)”. Revista De Biología Tropical, vol. 34, no. 2, Nov. 1986, pp. 243–246, https://revistas.ucr.ac.cr/index.php/rbt/article/view/24302.