It is established in the jurisprudence of the Enlarged Board of Appeal ever since decision G 5/83 (OJ 1985, 64, points 3 et seq. of the Reasons) that the principles of interpretation of Arts. 31 and 32 of the Vienna Convention are to be applied to the interpretation of the EPC even though its provisions do not apply to the EPC ex lege. In J 10/98 (OJ 2003, 184) the Legal Board of Appeal stated that, although the Vienna Convention did not expressly apply to the interpretation of EPC, PCT or the Paris Convention, since it came into force at a later date than all of those treaties, in accordance with what had been recognised by the Enlarged Board of Appeal in decision G 5/83, its principles of interpretation were a valuable guide to the interpretation of all treaties executed both before and after it. In T 1173/97 (OJ 1999, 609) the board stated that although the Vienna Convention is not applicable to the EPC, it has considerable authority and has frequently been cited by the boards of appeal when applying principles laid down in it.