http://www.seaslugforum.net/showall/bullnobi
http://gastropods.com/3/Shell_10863.shtml
http://vieoceane.free.fr/mollusques/Bullinidae.htm
http://www.umiushi-zukan.com/eng/list_pic.php?ssw=g&kind_id=507
http://www.nmr-pics.nl/Bullinidae/album/index.html
http://www.medslugs.de/E/Ind-SW/Bullina_nobilis/Selection.htm