Use the OrderReference element to specify this on a Document Level.

Elements

Element	Description
`Invoice/OrderReference/ID`	Specify the reference to the additional document.

Country Specific Configurations

Netherlands: Order Line References

Example

<ubl:Invoice xmlns:ubl="urn:oasis:names:specification:ubl:schema:xsd:Invoice-2" xmlns:cac="urn:oasis:names:specification:ubl:schema:xsd:CommonAggregateComponents-2" xmlns:cbc="urn:oasis:names:specification:ubl:schema:xsd:CommonBasicComponents-2" xmlns:cec="urn:oasis:names:specification:ubl:schema:xsd:CommonExtensionComponents-2" xmlns:vrbl="urn:vertexinc:vrbl:ExtensionComponent:1.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="urn:oasis:names:specification:ubl:schema:xsd:Invoice-2 ../../../../vrbl/maindoc/UBL-Invoice-2.4.xsd">
<-- Code omitted for clarity -->
	<cbc:DocumentCurrencyCode>RON</cbc:DocumentCurrencyCode>
	<cac:OrderReference>
		<cbc:ID>PO987654</cbc:ID>
	</cac:OrderReference>