View of the Sheikh Ora crater, looking south, sketched from a sailing boat.
<a href="https://de.wikipedia.org/wiki/Felix_Oswald" class="extiw" title="de:Felix Oswald">de:Felix Oswald</a>
1906-01-01
Oswald, Felix (1906) <cite>A Treatise on the Geology of Armenia</cite><sup><a rel="nofollow" class="external autonumber" href="https://books.google.com/books?id=veAQAAAAIAAJ&amp;pg=PA102-IA2">[1]</a></sup>