Judgment of the Court (First Chamber) of 26 May 2005 in Case C-283/03: Reference for a preliminary ruling from the College van Beroep voor het bedrijfsleven A.H. Kuipers v Productschap Zuivel (Common organisation of the markets — Milk and milk products — Regulation (EEC) No 804/68 — National scheme under which dairies withhold deductions from the price payable to dairy farmers or pay price supplements to them according to the quality of the milk supplied — Incompatibility)