Actually actually, it's even more complicated than that! Works published between 1925 and 1978 needed to file a copyright extension notice before the 28th anniv

Actually actually, it's even more complicated than that! Works published between 1925 and 1978 needed to file a copyright extension notice before the 28th anniversary of initial publication or the work fell into public domain. Copyright law is a maze whose rules have changed numerous times over the decades. Here's a pretty good flowchart for U.S. copyright: https://www.sunsteinlaw.com/copyright-flowchart https://www.sunsteinlaw.com/copyright-flowchart