17 U.S.C. § 204 — Execution of transfers of copyright ownership

(a) A transfer of copyright ownership — except one that happens automatically "by operation of law," like through inheritance — isn't valid unless it's written down. This can be a formal document, or just a note or memo, but it must be signed by the person giving up the rights, or by their authorized agent. (b) The transfer doesn't need a notarized "certificate of acknowledgement" to be valid. But having one serves as strong initial proof that the transfer really happened, if: (1) for a transfer made in the U.S., the certificate comes from someone authorized to administer oaths in the U.S.; or (2) for a transfer made in another country, the certificate comes from a U.S. diplomat or consular officer, or from someone else authorized to administer oaths whose authority a U.S. diplomat or consular officer has certified.