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 maps: Armand Casini; "On the Ridgetop": Jacques Parker; "Crossing the Po": no signature from ''Mountaineers'', pamphlet published c.1950 (according to Library of Congress entry), no copyright notice in pamphlet with UploadWizard