Günter Siebert (left) - german carom billiards player
Unknown author<span style="display: none;">Unknown author</span>
<a href="https://de.wikipedia.org/wiki/User:Carambol" class="extiw" title="de:User:Carambol">Carambol</a> (got it from the private archive of Günter Siebert-personally known)