Article 66
By way of derogation from Articles 63, 64 and 65, Member States may provide that VAT is to become chargeable, in respect of certain transactions or certain categories of taxable person at one of the following times:
(a)
no later than the time the invoice is issued;
(b)
no later than the time the payment is received;
(c)
where an invoice is not issued, or is issued late, within a specified period from the date of the chargeable event.