Tjalling Koopmans receiving an honorary doctorate from Albert Descamps, rector of Catholic Universiyt Leuven. Left: Atoine Braun and  W.A. Visser 't Hooft; right: probably Pieter de Somer. Leuven, 2 Febr. 1967
<a href="//commons.wikimedia.org/wiki/Category:Eric_Koch" title="Category:Eric Koch">Eric Koch</a> for <a href="//commons.wikimedia.org/wiki/Category:Anefo" title="Category:Anefo">Anefo</a>
1967-02-02
<a rel="nofollow" class="external text" href="http://proxy.handle.net/10648/ab0e6646-d0b4-102d-bcf8-003048976d84">GaHetNa (Nationaal Archief NL)</a> 920-0381