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 (70 years p.m.a.), Mainland China (50 years p.m.a., not Hong Kong or Macao), Germany (70 years p.m.a.), Mexico (100 years p.m.a.), Switzerland (70 years p.m.a.), and other countries with individual treaties.
The publication of the 1961 Golden Tulip cards was not copyright at the time (see back of the card here, and no copyrights were registered at the US copyight office (see here.
File history
Click on a date/time to view the file as it appeared at that time.