http://www.habitas.org.uk/marinelife/species.asp?item=W13010 http://www.tmbl.gu.se/libdb/taxon/Okenia.html http://www.medslugs.de/E/Atl-NE/Okenia_aspersa/Selection.htm http://www.medslugs.de/E/Med/Okenia_aspersa/Selection.htm