applic articl sixth council direct ad tax author derog draft agreement feder republ germani luxembourg eec letter date decemb german luxembourg govern inform commiss pursuant provis intent introduc measur derog sixth direct view part draft agreement germani luxembourg vat levi construct mainten work frontier bridg german author feder republ germani assum respons oper commiss inform member state letter date januari request submit german luxembourg govern accord articl sixth direct council decis author derog deem adopt month member state inform commiss member state request matter rais council commiss member state request matter rais time limit council decis deem adopt march oj