Signature of Niels Bohr.
<a href="//commons.wikimedia.org/wiki/User:Connormah" title="User:Connormah">Connormah</a>, Niels Bohr
Own work by uploader, traced in Adobe Illustrator from <a href="https://en.wikipedia.org/wiki/File:Niels_Bohr-sig.jpg" class="extiw" title="w:File:Niels Bohr-sig.jpg">w:File:Niels Bohr-sig.jpg</a>