Judgment of the Court of 21 February 1991 in Joined Cases C-143/88 and C-92/89: (references for a preliminary ruling made by the Finanzgericht Hamburg and the Finanzgericht Dusseldorf (Federal Republic of Germany) Zuckerfabrik Siiderdithmarschen AG v. Hauptzollamt Itzehoe and Zuckerfabrik Soest GmbH v. Hauptzollamt Paderborn (Jurisdiction of national courts in proceedings for interim relief to suspend the operation of a national measure based on a Community regulation — Validity of the special elimination levy in the sugar sector)