<p>at the railroad station of Leiden. People on the picture from left to right: 
</p>
<ul><li><a href="https://en.wikipedia.org/wiki/Niels_Bohr" class="extiw" title="en:Niels Bohr">Bohr, N.</a>;</li>
<li><a href="https://en.wikipedia.org/wiki/Paul_Ehrenfest" class="extiw" title="en:Paul Ehrenfest">Ehrenfest, Paul</a>;</li>
<li>Paul, Jr. ('Pavlik') (1915–1939)</li></ul>
Photo by Paul Ehrenfest's (1880-1933) associate.
circa 1922 <div style="display: none;">date QS:P,+1922-00-00T00:00:00Z/9,P1480,Q5727902</div>
<a rel="nofollow" class="external free" href="http://www.th.physik.uni-frankfurt.de/~jr/gif/phys/bohrfest32.jpg">http://www.th.physik.uni-frankfurt.de/~jr/gif/phys/bohrfest32.jpg</a>