Signatur von <a href="https://de.wikipedia.org/wiki/Albert_Volkart" class="extiw" title="de:Albert Volkart">Albert Volkart</a>
Albert Volkart
circa 1925 <div style="display: none;">date QS:P,+1925-00-00T00:00:00Z/9,P1480,Q5727902</div>
<a rel="nofollow" class="external text" href="https://doi.org/10.3932/ethz-a-000045693">e-pics Bildarchiv online</a>, ETH Bibliothek