Jean-Christophe Vié (International Union for Conservation of Nature and Natural Resources),Craig Hilton-Taylor (International Union for Conservation of Nature and Natural Resources),Simon N. Stuart (International Union for Conservation of Nature and Natural Resources) 2009: Wildlife in a Changing World: An analysis of the 2008 IUCN Red List of Threatened Species, <https://portals.iucn.org/library/node/9356>