A group of business terms providing information about additional supporting documents substantiating the claims made in the Invoice. The additional supporting documents can be used for both referencing a document number which is expected to be known by the receiver, an external document (referenced by a URL) or as an embedded document, Base64 encoded (such as a time report).
Invoiced object identifier, Supporting document reference or project reference
Document type code
Supporting document description
Only one invoiced object is allowed on document level
Only one project reference is allowed on document level