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Chess on Stamps
Chess on Stamps Study Unit (COSSU)
The COSSU is a group of collectors who are interested in the thematic "Chess-on-Stamps." There are occasional mail auctions held, where members buy and sell their duplicate material.
Chess is Fun - Jon Edwards (USA)
Jon Edwards, the United States Correspondence Chess Champion, has an intriguing Chess on Stamps Exhibit - in addition to the images, you will often find relevant chess games.
Chess on Stamps - Colin Rose (Australia)
A gallery of chess stamps, as well as a chess stamp catalog that is organized according to date, country, and theme.