Elements

Element	Description
Document Reference Extension Group (`DocumentReference/UBLExtensions/UBLExtension/ExtensionContent/ DocumentReferenceExtension/`)	Groups extended document reference information.
Line ID (`DocumentReference/UBLExtensions/UBLExtension/ExtensionContent/ DocumentReferenceExtension/LineID`)	The line in the Commitment Document that you are referencing.
ID (`Invoice/InvoiceLine/DocumentReference/ID`)	Specify the referenced document's ID.
Scheme Identifier (`Invoice/InvoiceLine/DocumentReference/ID @schemeID`)	Use `VRBL:PT:COMMITMENT`.

Country-Specific configurations

Portugal: Document Reference ID

Example

 <!-- Code omitted for clarity -->
        <cac:DocumentReference>
            <cec:UBLExtensions>
                <cec:UBLExtension>
                    <cec:ExtensionContent>
                        <vrbl:DocumentReferenceExtension>
                            <cbc:LineID>01</cbc:LineID>
                        </vrbl:DocumentReferenceExtension>
                    </cec:ExtensionContent>
                </cec:UBLExtension>
            </cec:UBLExtensions>
            <cbc:ID schemeID="VRBL:PT:COMMITMENT">12345678</cbc:ID>
            <cbc:IssueDate>2024-05-02</cbc:IssueDate>
        </cac:DocumentReference>
        <!-- Code omitted for clarity -->
    </cac:InvoiceLine>
    <!-- Code omitted for clarity -->
</ubl:Invoice>