|Ted Williams, Willie Stargell, Joe DiMaggio, and Larry Doby|
|The back is not blank, which I think makes it that much more collectible!|
I did some research to find out that this set was released July 2012. As for what I read that the stamps were released in the four cities of the players pictured, Pittsburgh, Boston, New York, and Cleveland. Nearly two million of these sheets were produced and over the past year a few sheets have migrated to Post Offices across the country. If you can't find these at any of your Post Offices and instead of buying on Ebay you can still buy them here: http://stampproducts.com/playball/ .
Now I think I'm going to start looking for a new frame for these beauties!