http://www.medslugs.de/E/Med/Petalifera_petalifera/Selection.htm
http://rfbolland.com/okislugs/petapeta.html
http://www.marenostrum.org/opistobranquios/ppetalifera/ppetalifera.htm
http://www.seaslugforum.net/showall/petapeta
http://www.umiushi.info/photo_species/photo_splist_eng.php?sopt=0&loc=0000
http://www.nudipixel.net/species/petalifera_petalifera/
http://opistobranquis.info/en/guia/anaspidea/petalifera-petalifera/
http://www.medslugs.de/E/Atl-E/Petalifera_petalifera/Selection.htm