The beak of a <a href="//commons.wikimedia.org/wiki/Category:Mergus" title="Category:Mergus">Mergus</a>
<a href="//commons.wikimedia.org/wiki/Nordisk_familjebok" title="Nordisk familjebok">Nordisk familjebok</a> (1904), vol.1, p.958 <a rel="nofollow" class="external autonumber" href="http://runeberg.org/nfba/0541.html">[1]</a>