The referenced document as an attachment to the document from which it is referenced.

Namespace
cac urn:oasis:names:specification:ubl:schema:xsd:CommonAggregateComponents-2
Data type
Attachment
Child elements
Card Name Description
1..1 cac:External Reference

External reference
A reference to an attached document that is external to the document(s) being exchanged.

Rules
Identifier/Error message Flag
PEPPOL-T013-S316
[PEPPOL-T013-S316] Attachment SHOULD NOT contain any elements but ExternalReference
warning