Used to reference the order that is being responded to.

Cardinality
1..1
Namespace
cbc urn:oasis:names:specification:ubl:schema:xsd:CommonBasicComponents-2
Data type
Document reference
Example value
o-23424
Business terms
tir76-011
Rules
Identifier/Error message Flag
EHF-T76-B01301
Document MUST NOT contain elements not part of the data model.
fatal