Portret van Karl Popper (1902-1994)
<a href="//commons.wikimedia.org/wiki/User:Mdd" title="User:Mdd">Marcel Douwe Dekker</a>
CC BY-SA 4.0
<span class="int-own-work" lang="en">Own work</span>, derived from <a href="//commons.wikimedia.org/wiki/File:Karl_Popper2.jpg" title="File:Karl Popper2.jpg">File:Karl Popper2.jpg</a>