This non-U.S. work was published in 1929 or later, but is in the public domain in the United States because it was simultaneously published (within 30 days) in the U.S. and in its source country (Spain) and is in the public domain in the U.S. as a U.S. work (no copyright registered, or not renewed). For background information, see the explanations on Non-U.S. copyrights. reason
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.