Warsaw Ghetto postage stamp, denomination 15, never issued

http://lod.ehri-project-test.eu/units/us-005578-irn524138-irn519012 an entity of type: Record

The Warsaw ghetto stamp was donated to the United States Holocaust Memorial Museum in 2007 by Alfred Moritz. 
1941 April 
irn519012 
Warsaw Ghetto postage stamp, denomination 15, never issued 
overall: Height: 1.375 inches (3.493 cm) | Width: 1.875 inches (4.763 cm) 
Warsaw ghetto stamp marked 15 issued by the Warsaw Ghetto Resistance Organization (Żydowski Zwia̜zek Wojskowy). The Warsaw Ghetto in Poland existed from October 12, 1940, to May 16, 1943, when the Ghetto was liquidated by German forces. The stamps were manufactured in an effort to establish a ghetto mail office by the underground, but were not issued for use. 
No restrictions on access 
No restrictions on use 
Square paper stamp with a graphic design stamped in blue ink on the front with the denomination 15, a Star of David with radiating lines, an outlined border, and Polish text. The reverse is blank. 

data from the linked data cloud