Erhard signing at <a href="https://en.wikipedia.org/wiki/Museum_Angewandte_Kunst" class="extiw" title="en:Museum Angewandte Kunst">Museum Angewandte Kunst</a>.
<a href="//commons.wikimedia.org/wiki/User:Ptolusque" title="User:Ptolusque">Ptolusque</a>
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<span class="int-own-work" lang="en">Own work</span>