http://www.pictonb.freeserve.co.uk/nudibranchs/facdub.html
http://www.medslugs.de/E/Med/Facelina_dubia/Selection.htm
http://www.seaslugforum.net/showall/facedubi
http://opistobranquis.info/en/guia/nudibranchia/dexiarchia/aeolidida/facelina-dubia/