<a href="https://en.wikipedia.org/wiki/en:Allvar_Gullstrand" class="extiw" title="w:en:Allvar Gullstrand">Allvar Gullstrand</a>
Unknown author<span style="display: none;">Unknown author</span>
Unknown date<div style="display: none;">Unknown date</div>, published in 1912 in Sweden in <a rel="nofollow" class="external text" href="https://www.archive.org/details/lesprixnobel1911nobe">Les Prix Nobel</a>, p. 64
<a rel="nofollow" class="external free" href="http://wwwihm.nlm.nih.gov/ihm/images/B/13/800.jpg">http://wwwihm.nlm.nih.gov/ihm/images/B/13/800.jpg</a>