[BobC]

I also have a small collection of these, and had just been looking at Leon's scan of them in the other post about the pre-war collector survey thread. Talk about an unbelievable coincidence in timing, especially on such an obscure subject. As the others have already stated, these were printed in various papers across the country during the Summer of 1936. Some over the entire season, others during just a couple months (July and August) or some other limited period, or in the case of the Pittsburgh paper, all printed at one time in a single edition. Besides major league baseball players, some newspapers also included people from different sports, like car racing and even promoters, as well as minor league/local ballplayers in some instances. And for whatever reasoning, these weren't like syndicated comic strips back then where every different newspaper showed the exact same comic on the exact same day. Seems each individual paper had some discretion over who was or wasn't included, and when/how these were printed, even though the somewhat consistent format and design of the Sports Stamps would seem to indicate a common source/originator for the idea.

Leon's scan already includes examples of most of the known papers these were printed in. And then there are the newspapers mentioned by some others that are also known to have printed these Sports Stamps in them. The following is a list of newspapers I'm aware of, or that have already been mentioned, as having printed Sports Stamps.

Atlanta-Georgian American
Boston American (Checklisted in SCD catalog)
Chicago American
Detroit Times (Checklisted in SCD catalog)
Los Angeles Examiner
Pittsburgh Sun-Telegraph (Checklisted in SCD catalog)
Sunday Advertiser (Checklisted in SCD catalog)
The Sporting News
Washington Herald

As i noted above, four of the listed newspapers were included in the Krause/SCD annual sports catalogs that used to be printed up to a few years ago. In them they included a small descrition of the sets, as well as checklists. The Sunday Advertiser listing does not have any separate info and refers the reader back to the Boston American checklist and description. The Boston American checklist does not include Greenberg, but the description for the set notes the checklist is possibly not complete, so he may still have been in those papers. The Detroit and Pittsburgh checklists both show Greenberg was part of those sets, and also mention the listed checklists for both are likely incomplete as well. Don't really know the specifics or checklists for sets in the other known newspapers these were printed in.
Hope this helps, good luck.