<a href="https://en.wikipedia.org/wiki/Alexander_Stepanovich_Popov" class="extiw" title="w:Alexander Stepanovich Popov">Alexander Popov</a> signature
Extracted and traced from <a rel="nofollow" class="external free" href="http://www.physics.uni-altai.ru/journals/physics/2002/20/no20_15.jpg">http://www.physics.uni-altai.ru/journals/physics/2002/20/no20_15.jpg</a>
<a href="//commons.wikimedia.org/wiki/User:Yuriybrisk" title="User:Yuriybrisk">Yuriy Lapitskiy</a>, Alexander Popov
2010-03-05
<span class="int-own-work" lang="en">Own work</span> work by uploader traced by hand