“In the light of all those considerations, the answer to the question submitted by the Corte Suprema di Cassazione must be that the third paragraph of Article 177 of the EEC Treaty is to be interpreted as meaning that a court or tribunal against whose decisions there is no judicial remedy under national law is required, where a question of Community law is raised before it, to comply with its obligation to bring the matter before the Court of Justice, unless it has established that the question raised is irrelevant or that the Community provision in question has already been interpreted by the Court or that the correct application of Community law is so obvious as to leave no scope for any reasonable doubt. The existence of such a possibility must be assessed in the light of the specific characteristics of Community law, the particular difficulties to which its interpretation gives rise and the risk of divergences in judicial decisions within the Community.”