Under Article 3.1, the agency of the country whose social security coverage laws will continue to apply to a person in accordance with the various rules set forth in Part II of the Agreement will issue a certificate to that effect when requested to do so by an employer or a self-employed person. Certificates should be requested before beginning work in the other country, whenever possible. When presented to the appropriate agency of the other country, the certificate will serve as evidence of the exemption of the person from the coverage laws of that country. Retroactive recovery of U.S. contributions paid with respect to services for which a coverage exemption has been in effect would be subject to the time limitations for refunds of taxes in the Internal Revenue Code.
