Martínez, J.; Wallace, R. B.; López-Strauss, H.; Torre, P.; Aranibar, H. Two New Specimens for the Bolivian Endemic Titi Monkeys, Callicebus Olallae and Callicebus Modestus. Neotrop. Primates 2013, 20 (1), 39-44. https://doi.org/10.1896/044.020.0106.