Smithsonian Magazine

January 2019 

 

"At midnight on New Year’s Eve, all works first published in the United States in 1923 will enter the public domain. It has been 21 years since the last mass expiration of copyright in the U.S."

 

 

 https://www.smithsonianmag.com/arts-culture/first-time-20-years-copyrighted-works-enter-public-domain-180971016/