http://www.seaslugforum.net/showall/bertagas
http://www.inbio.ac.cr/papers/babosasmarinas/ingles/listadeesp.htm
http://www.medslugs.de/E/Pac-E/Berthella_agassizii/Selection.htm
http://www.nudipixel.net/species/berthella_agassizi/