Depending on the kind of the goods, the document may be:
Letter or invoice by the manufacturer, specifying the origin of the exported goods, in compliance with the rules for preferential treatment or,
Copy of a customs declaration for the importation of the goods, certificate "EUR.1" or another certificate of origin, issued and validated by a competent foreign institution (for foreign origin), or,
Quality certificate, or,
Phytosanitary certificate (for exports of goods of vegetable origin), or,
Veterinarian certificate (for exports of animal goods), or,
Analysis or laboratory certificate (for exports of medicines, cosmetics, medicines, chemical preparations, etc.), or,