Article 4

Certificates of authenticity shall be valid only if they are duly completed and endorsed, in accordance with the instructions given at Annex II, by the issuing authority.

A certificate of authenticity shall be deemed to have been duly endorsed if it specifies the date and place of issue and if it bears the stamp of the issuing authority and the signature of the person or persons empowered to sign it.

The stamp may be replaced on the original certificate of authenticity and its copies by a printed seal.