English: Found on Football Card Gallery. The publication of the 1969 Glendale Stamps was not copyrighted at the time (the back of the stamp was left blank) and no copyrights were registered at the US copyright office.
Note that it may still be copyrighted in jurisdictions that do not apply the rule of the shorter term for US works (depending on the date of the author's death), such as Canada (50 p.m.a.), Mainland China (50 p.m.a., not Hong Kong or Macao), Germany (70 p.m.a.), Mexico (100 p.m.a.), Switzerland (70 p.m.a.), and other countries with individual treaties.
Uploaded a work by Glendale Stamps from [https://www.footballcardgallery.com/card/69gs/191/1969-glendale-stamps-mick-tingelhoff/ Football Card Gallery] with UploadWizard