Sheet of US Postage stamps, 1940 issue, partial image, featuring perforations.
<a href="https://en.wikipedia.org/wiki/Bureau_of_Engraving_and_Printing" class="extiw" title="wikipedia:Bureau of Engraving and Printing">Bureau of Engraving and Printing</a>; Imaging by <a href="//commons.wikimedia.org/wiki/User:Gwillhickers" title="User:Gwillhickers"><i>Gwillhickers</i></a>
1940-01-29
U.S. Post Office<a href="https://en.wikipedia.org/wiki/user:Gwillhickers" class="extiw" title="wikipedia:user:Gwillhickers">Gwillhickers</a>: Photo of sheet of stamps from private collection