Reference
Markdown exportBT-122 Supporting Document Reference
An identifier for a supporting document referenced from the invoice.
Quick answer
Taxes and totals
VAT treatment, tax breakdowns, and document totals that validators check closely.
Quick actions
In plain language
Links the invoice to evidence such as contracts, delivery notes, timesheets, or other attachments.
What you usually enter here
Document identifier
Typical valid values include: DELIVERY-NOTE-1001, CONTRACT-2025-07, TIMESHEET-42
Each supporting document group must contain a supporting document reference according to BR-52.
Where the field sits
- Invoice
- cac:AdditionalDocumentReference[not(cbc:DocumentTypeCode="130")]
- cbc:IDBT-122
- rsm:CrossIndustryInvoice
- rsm:SupplyChainTradeTransaction
- ram:ApplicableHeaderTradeAgreement
- ram:AdditionalReferencedDocument[ram:TypeCode="916"]
- ram:IssuerAssignedIDBT-122
What goes wrong often
Relevant rule codes: BR-52
Valid Examples
- DELIVERY-NOTE-1001
- CONTRACT-2025-07
- TIMESHEET-42
XML mapping and field facts
Open the technical reference if you need XML paths, validator rule codes, legal wording, or schema-specific mapping details.
Field ID:
BT-122
Data Type:
identifier
Cardinality:
1..1
Requirement:
Mandatory
XML Implementation
/Invoice/cac:AdditionalDocumentReference[not(cbc:DocumentTypeCode="130")]/cbc:ID/rsm:CrossIndustryInvoice/rsm:SupplyChainTradeTransaction/ram:ApplicableHeaderTradeAgreement/ram:AdditionalReferencedDocument[ram:TypeCode="916"]/ram:IssuerAssignedIDValidation Rules
BR-52
BR-52
Next step
Check whether your XRechnung sets BT-122 correctly
Upload the XML file to the free validator. It applies the KoSIT rules for XRechnung 3.0 and names each finding with its rule ID, for this field for example BR-52. Creating a new invoice instead? The converter checks the invoice against the same rules and shows the findings before download.
Free, no account needed. XML file up to 2 MB.