15In that connection, the Commission argues, first, that the effectiveness of the national tax system cannot be threatened in so far as there are other appropriate instruments by which it may be ensured, such as Council Directive 76/308/EEC of 15 March 1976 on mutual assistance for the recovery of claims relating to certain levies, duties, taxes and other measures (OJ 1976 L 73, p. 18), as amended by Council Directive 2001/44/EC of 15 June 2001 (OJ 2001 L 175, p. 17) (‘Directive 76/308’), Council Directive 77/799/EEC of 19 December 1977 concerning mutual assistance by the competent authorities of the Member States in the field of direct taxation and taxation of insurance premiums (OJ 1977 L 336, p. 15), as amended by Council Directive 2004/106/EC of 16 November 2004 (OJ 2004 L 359, p. 30) (‘Directive 77/799’), and Council Directive 2008/55/EC of 26 May 2008 on mutual assistance for the recovery of claims relating to certain levies, duties, taxes and other measures (OJ 2008 L 150, p. 28).