http://www.seaslugforum.net/showall/gastbico
http://www.ne.jp/asahi/kappa-kuri/miyamoto/OSEHOO/umiushi125.html
https://www.Philippine-Sea-Slugs.com/Cephalaspidea/Gastropteron_bicornutum.htm
http://www.nudipixel.net/species/gastropteron_bicornutum/
http://www.nudibranch.org/Sulawesi Sea Slugs/html/sss-sea-slugs.html
http://www.umiushi-zukan.com/eng/list_pic.php?ssw=g&kind_id=516
http://www.medslugs.de/E/Ind-E/Gastropteron_bicornutum/Selection.htm
http://slugsite.us/bow2007/nudwk978.htm
http://www.medslugs.de/E/Ind-NW/Gastropteron_bicornutum/Selection.htm
http://www.vibrantsea.net/gastropteron5417_anilao2017.htm
http://www.medslugs.de/E/Ind-SW/Gastropteron_bicornutum/Selection.htm