Verso of any "Doha" model international reply coupon. This particular coupon was issued by the Vatican City State.
<a href="//commons.wikimedia.org/w/index.php?title=User:Gio.B.R.&amp;action=edit&amp;redlink=1" class="new" title="User:Gio.B.R. (page does not exist)">Gio.B.R.</a>
<span class="int-own-work" lang="en">Own work</span>