Blick in das Atelier von <a href="//commons.wikimedia.org/wiki/Category:Otto_Heinrich_Engel" title="Category:Otto Heinrich Engel">Otto H. Engel</a>, 1912
<a rel="nofollow" class="external text" href="https://portal.dnb.de/opac.htm?method=simpleSearch&amp;cqlMode=true&amp;query=idn%3D1101364114">Hermann Boll (1848 - ?)</a>
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