Copyright catalogs at the Library of Congress. Located in room LM-404 of the James Madison Memorial Building, Washington DC. The pre-1978 indexes to the copyright records were manually entered on 3 by 5 inch (76 by 127 mm) cards that were stored in file drawers.
Michael Holley <a href="//commons.wikimedia.org/wiki/User:Swtpc6800" title="User:Swtpc6800">Swtpc6800</a>
<span class="int-own-work" lang="en">Own work</span>