In its judgment of 25 July 2002, in Case C-50/00 P, Unión de Pequeños Agricultores, the Court of Justice points out that, under the Community system of legal remedies and procedures, where natural or legal persons cannot, by reason of the conditions for admissibility laid down in the fourth paragraph of Article 173 of the Treaty (now Article 230), directly challenge Community measures of general application, they are able, depending on the case, either indirectly to plead the invalidity of such acts before the Community Courts under Article 184 of the Treaty (now Article 241) or to do so before the national courts and to ask them, since they have no jurisdiction themselves to declare those measures invalid, to make a reference to the Court of Justice for a preliminary ruling on validity.