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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 (2015). "Ancient protein resolve the evolutionary history of Darwin's South American ungulates". Nature. 522 (7554): 81–84. Bibcode:2015Natur.522...81W. doi:10.1038/nature14249. hdl:11336/14769. PMID25799987. S2CID4467386.
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 (2015). "Ancient protein resolve the evolutionary history of Darwin's South American ungulates". Nature. 522 (7554): 81–84. Bibcode:2015Natur.522...81W. doi:10.1038/nature14249. hdl:11336/14769. PMID25799987. S2CID4467386.
William Berryman Scott (1941). "Part V: Perissodactyla". The Mammalian Fauna of the White River Oligocene Transactions of the American Philosophical Society. New Series. 28 (5): 747–964. doi:10.2307/1005518. JSTOR1005518.
Dan Graur; Manolo Gouy; Laurent Duret (1997). "Evolutionary Affinities of the Order Perissodactyla and the Phylogenetic Status of the Superordinal taxa Ungulata and Altungulata Molecular Phylogenetics and Evolution". Molecular Phylogenetics and Evolution. 7 (2): 195–200. doi:10.1006/mpev.1996.0391. PMID9126561.
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 (2015). "Ancient protein resolve the evolutionary history of Darwin's South American ungulates". Nature. 522 (7554): 81–84. Bibcode:2015Natur.522...81W. doi:10.1038/nature14249. hdl:11336/14769. PMID25799987. S2CID4467386.
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 (2015). "Ancient protein resolve the evolutionary history of Darwin's South American ungulates". Nature. 522 (7554): 81–84. Bibcode:2015Natur.522...81W. doi:10.1038/nature14249. hdl:11336/14769. PMID25799987. S2CID4467386.
Ravel, Anthony; Orliac, Maeva (2014). "The inner ear morphology of the 'condylarthran' Hyopsodus lepidus". Historical Biology. 27 (8): 8. doi:10.1080/08912963.2014.915823. S2CID84391276.
Gong, Y.; Wang, Y.; et al. (December 2019). "Dietary adaptations and palaeoecology of Lophialetidae (Mammalia, Tapiroidea) from the Eocene of the Erlian Basin, China: combined evidence from mesowear and stable isotope analyses". Palaeontology. 63 (4): 547–564. doi:10.1111/pala.12471. S2CID214053761.
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 (4): 895–901. doi:10.1080/02724634.2011.579669. S2CID84351811.
Kenneth D. Rose; Thierry Smith; Rajendra S. Rana; Ashok Sahni; H. Singh; A. Pieter Missiaen (2006). "Early Eocene (Ypresian) Continental vertebrate assemblage from India, with description of a new anthracobunid (Mammalia, tethytheria )". Journal of Vertebrate Paleontology. 26: 219–225. doi:10.1671/0272-4634(2006)26[219:eeycva]2.0.co;2. S2CID86206151.
Pieter Missiaen; Gregg F. Gunnell; Philip D. Gingerich (2011). "New brontotheriidae (Mammalia, Perissodactyla) from the Early and Middle Eocene of Pakistan with implications for mammalian paleobiogeography". Journal of Paleontology. 85 (4): 665–677. doi:10.1666/10-087.1. S2CID129473193.
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 (2015). "Ancient protein resolve the evolutionary history of Darwin's South American ungulates". Nature. 522 (7554): 81–84. Bibcode:2015Natur.522...81W. doi:10.1038/nature14249. hdl:11336/14769. PMID25799987. S2CID4467386.