To cite the Red List generally use the following format, changing the dates where appropriate:
IUCN 2009. IUCN Red List of Threatened Species. Version 2009.2. <http://www.iucnredlist.org>.
Downloaded on 03 November 2009.
To cite a specific assessment, use the assessor/s name/s, the date the assessment was done, the taxon name followed by the above citation. For example:
Leary et al. 2008. Zaglossus bruijni. In: IUCN 2009. IUCN Red List of Threatened Species. Version 2009.2. <http://www.iucnredlist.org/apps/redlist/details/23179>. Downloaded on 03 November 2009.
Sotomayor, M.M., Arredondo, A.G., Sánchez, B., Dicht, R.F. & Lüthy, A.D. 2002. Coryphantha maiz-tablasensis. In: IUCN 2009. IUCN Red List of Threatened Species. Version 2009.2. <http://www.iucnredlist.org/apps/redlist/details/40819>. Downloaded on 03 November 2009.
