Integrated Taxonomic Information System (ITIS): Strix ocellata (TSN 555426)itis.gov. Viitattu 3.3.2012. (englanniksi)
iucnredlist.org
BirdLife International: Strix ocellataIUCN Red List of Threatened Species. Version 2013.2. 2012. International Union for Conservation of Nature, IUCN, Iucnredlist.org. Viitattu 20.5.2014. (englanniksi)