council decis decemb author kingdom spain appli measur accord articl direct eec eec council european commun regard treati establish european econom commun regard sixth council direct eec harmon law member state relat turnov tax common system ad tax uniform basi assess articl thereof regard propos commiss articl direct eec council act unanim propos commiss author member state introduc measur simplifi statement oblig laid paragraph articl articl stipul simplif measur jeopard proper monitor intra commun transact form outlin subparagraph articl spanish govern letter receiv commiss august request author simplif measur take form laid subparagraph articl author temporari measur affect european commun resourc aris ad tax adopt decis articl provid articl direct eec kingdom spain author effect januari decemb end transit arrang event introduc measur accord subparagraph articl simplifi oblig laid paragraph articl recapitul statement articl decis address kingdom spain brussel decemb council presid hurd oj direct amend direct eec oj