Édouard Otlet en 1887.
Unknown author<span style="display: none;">Unknown author</span>
<a href="//commons.wikimedia.org/wiki/File:%C3%89douard_Otlet_en_1887.jpg" title="File:Édouard Otlet en 1887.jpg">File:Édouard Otlet en 1887.jpg</a>