Johnson & Madden 1997. Uruguaytheriine astrapotheres of tropical South America. Kay, Richard F.; Madden, Richard H.; Cifelli, Richard L.; Flynn, John J.[Eds]. Vertebrate paleontology in the Neotropics: the Miocene fauna of La Venta, Colombia., Smithsonian Institution Press, Washington & London, 1997: i-xv, 1-592. Chapter pagination: 355-382