xmlns:atom="http://www.w3.org/2005/Atom" xmlns:atom="http://www.w3.org/2005/Atom"
For the purposes of this Directive, Member States shall accept documents or messages on paper or in electronic form as invoices if they meet the conditions laid down in this Chapter.
Any document or message that amends and refers specifically and unambiguously to the initial invoice shall be treated as an invoice.