French Mathematician <a href="https://en.wikipedia.org/wiki/Jean-Pierre_Bourguignon" class="extiw" title="w:Jean-Pierre Bourguignon">Jean-Pierre Bourguignon</a>
Gert-Martin Greuel
CC BY-SA 2.0 de
<a rel="nofollow" class="external text" href="https://opc.mfo.de/detail?photo_id=19216">Oberwolfach Photo Collection</a>, Photo ID: 19216