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.
Photo of label on record single published in 1954. First published in the U.S. between 1927 and 1977 without a copyright notice, therefore "in the public domain due to failure to comply with required formalities".
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