Library of Congress. Copyright Office. Supplementary copyright registration. Copyright Office, Library of Congress.
Chicago Style (17th ed.) CitationLibrary of Congress. Copyright Office. Supplementary Copyright Registration. Washington, D.C.: Copyright Office, Library of Congress.
MLA (9th ed.) CitationLibrary of Congress. Copyright Office. Supplementary Copyright Registration. Copyright Office, Library of Congress.
Warning: These citations may not always be 100% accurate.