Commission Regulation (EC) No 951/2003 of 28 May 2003 derogating from Regulation (EC) No 174/1999 laying down special detailed rules for the application of Council Regulation (EEC) No 804/68 as regards export licences and export refunds in the case of milk and milk products and Regulation (EC) No 800/1999 laying down common detailed rules for the application of the system of export refunds on agricultural products