<a href="//commons.wikimedia.org/wiki/Hugo_Gunckel_L%C3%BCer" class="mw-redirect" title="Hugo Gunckel Lüer">Hugo Gunckel Lüer</a>
Probably taken by Victoria Castillo (wife of Gunckel, granted by <a href="https://en.wikipedia.org/wiki/es:Usuario:Gunckelie" class="extiw" title="w:es:Usuario:Gunckelie">Ingried Gunckel C</a>), uploaded here by <a href="//commons.wikimedia.org/wiki/User:Penarc" title="User:Penarc">Penarc</a>
CC BY 3.0
<span class="int-own-work" lang="en">Own work</span>