↑ Frido Welker; Matthew J. Collins; Jessica A. Thomas; Marc Wadsley; Selina Brace; Enrico Cappellini; Samuel T. Turvey; Marcelo Reguero; Javier N. Gelfo; Alejandro Kramarz; Joachim Burger; Thomas Jane Oates; David A. Ashford; Peter D. Ashton; Keri Rowsell; Duncan M. Porter; Benedikt Kessler; Roman Fischer; Carsten Baessmann; Stephanie Kaspar; Jesper V. Olsen; Patrick Kiley; James A. Elliott; Christian D. Kelstrup; Victoria Mullin; Michael Hofreiter; Eske Willerslev; Jean-Jacques Hublin; Ludovic Orlando; Ian Barnes; Ross DE MacPhee. “Ancient protein resolve the evolutionary history of Darwin's South American ungulates”. Nature 522: 81–84. PMID25799987. doi:10.1038/nature14249.
↑ Luke T. Holbrook; Joshua Lapergola (2011). “A new genus of perissodactyl (Mammalia) from the Bridgerian of Wyoming, with comments on basal perissodactyl phylogeny”. Journal of Vertebrate Paleontology 31: 895–901. doi:10.1080/02724634.2011.579669.
