Szalay F.S. 1999. Classification of mammals above the species level: Review. Journal of Vertebrate Paleontology19 (1): 191–195. doi:10.1080/02724634.1999.10011133. JSTOR 4523980.
iucnredlist.org
"Initiatives". The IUCN Red List of threatened species. IUCN. April 2010.