A turkish stamp from with Al-Farabi's face
Unknown author<span style="display: none;">Unknown author</span>
<cite class="book" style="font-style:normal">(2017) <i> Scott Standard Postage Stamp Catalogue</i>, Scott Publishing  <small><a href="https://en.wikipedia.org/wiki/International_Standard_Book_Number" class="extiw" title="en:International Standard Book Number">ISBN</a>:  <a href="//commons.wikimedia.org/wiki/Special:BookSources/0894875120" title="Special:BookSources/0894875120">0894875120</a>. </small></cite>