Article 31
Mutual assistance 1. The Spanish customs authorities and the customs authorities of the other Member States shall provide each other, through the European Commission, with specimen impressions of stamps used in their customs offices for the issue of EUR.1 movement certificates and with the addresses of the customs authorities responsible for verifying those certificates and invoice declarations. 2. In order to ensure the proper application of this Regulation, Spain and the other Member States shall assist each other, through their respective customs administrations, in checking the authenticity of the EUR.1 movement certificates or the invoice declarations and the correctness of the information given in these documents.