1. Aguirre, E. (1963). Hippopotamus crusafonti n. sp. del Plioceno inferior de Arenas del Rey (Granada). Notas y Comunicaciones Del Instituto Geologico y Minero De Espana, 69, 215–230.
2. Alloing-Séguier, L., Lihoreau, F., Boisserie, J.-R., Charruault, A. L., Orliac, M., & Tabuce, R. (2014). Enamel microstructure evolution in anthracotheres (Mammalia, Cetartiodactyla) and new insights on hippopotamoid phylogeny. Zoological Journal of the Linnean Society, 171, 668–695.
3. Arnason, U., Gullberg, A., Solweig, G., Ursing, B., & Janke, A. (2000). The mitochondrial genome of the sperm whale and a new molecular reference for estimating eutherian divergence rate. Journal of Molecular Evolution, 50, 569–578.
4. Bengston, P. (1988). Open nomenclature. Palaeontology, 31(1), 223–227.
5. Bibi, F., Shabel, A. B., Kraatz, B. P., & Stidham, T. A. (2006). New fossil ratite (Aves: Palaeognathae) eggshell discoveries from the late Miocene Baynunah Formation of the United Arab Emirates Arabian Peninsula. Palaeontologia Electronica, 9(1), 1–13.