Fotoporträt von Friedrich Keller
<span lang="en">Anonymous</span><span style="display:none">Unknown author</span>
circa 1908 <div style="display: none;">date QS:P,+1908-00-00T00:00:00Z/9,P1480,Q5727902</div>
Schwäbisches Bilderblatt, Jg. 1 (1908), Nr. 50, 8.11.1908, S. 8