Stanford Launches Copyright Renewal Database
"An online database that enables people to search copyright-renewal records for books published in the United States between 1923 and 1963 has been launched by Stanford University Libraries and Academic Information Resources (SULAIR)."
Complete press release - http://news-service.stanford.edu/news/2007/april4/copy-040407.html
Copyright Renewal Database - http://collections.stanford.edu/determinator/