This image was acquired from
wikimedia. It was marked as Public Domain or CC0 and is free to use. To verify, go to the source and check the information there.
Keywords from Image Description:
Poland TABROMIK. AeroTarg Company in agreement with the Polish Ministry of Post Telegraph AeroTarg stamps had to be bought for airmail in addition to the normal express postage rate payable by usage of regular Polish stamps The stamps were designed by Wilhelm Rudy initials on the stamps and crudely lithographed The stamps were perforated