Identifier of the recieved tender document, must be the UUID of the received tender.

Namespace
cbc urn:oasis:names:specification:ubl:schema:xsd:CommonBasicComponents-2
Data type
Identifier
Rules
Identifier/Error message Flag
PEPPOL-T006-R013
[PEPPOL-T006-R013] The document reference Identifier MUST reference the Tender ID expressed in a UUID syntax (RFC 4122)
fatal