Keywords: Perforation US1940 issues-2c.jpg en Sheet of US Postage stamps 1940 issue partial image featuring perforations de Ein Bogen US-Briefmarken von 1940 zur Verdeutlichung des Begriffs Perforation U S Post OfficeGwillhickers Photo of sheet of stamps from private collection Bureau of Engraving and Printing; Imaging by Gwillhickers derivative work Lämpel 1940-01-29 <gallery>Perforations US1940 issues-2c jpg Englisch beschriftetes Original</gallery> Farbe und Kontrast optimiert Lämpel Perforations US1940 issues-2c jpg PD-USGov Stamps of the United States 1931-1940 Red stamps Stamp perforation |