BR-52: Supporting document reference (BT-122) is missing

What does this mean?

Every additional supporting document (BG-24) must contain a supporting document reference (BT-122), e.g. the number of a timesheet. It is missing or empty for at least one document.
In CII (BT-17/BT-18) and UBL (BT-18) the rule also checks tender or object identifiers stored in the same element: in CII every ram:AdditionalReferencedDocument, in UBL every cac:AdditionalDocumentReference, including the object identifier with DocumentTypeCode 130.

Typical causes

An attachment was given with file name or description only, but without a reference.
A tender or object identifier was output without a value.

How to fix the error

State a reference for every document, e.g. the document number or a unique name.
CII: ram:ApplicableHeaderTradeAgreement/ram:AdditionalReferencedDocument/ram:IssuerAssignedID, UBL: cac:AdditionalDocumentReference/cbc:ID.
Generate and validate the invoice again.

In E-Rechnungsfreund

In the invoice form ("Experte" view), section "Zusätzliche Dokumente (BG-24)" (additional documents), fill in the field "Referenz (BT-122)" (reference) for every document. In section "Objekt-Identifikatoren Header (BT-17/BT-18)" (object identifiers) check the field "Identifier (BT-17/BT-18)" of every entry.

Example

Wrong

<ram:AdditionalReferencedDocument>
  <ram:IssuerAssignedID></ram:IssuerAssignedID>
  <ram:TypeCode>916</ram:TypeCode>
  <ram:Name>Timesheet March</ram:Name>
</ram:AdditionalReferencedDocument>

Correct

<ram:AdditionalReferencedDocument>
  <ram:IssuerAssignedID>TS-2026-03</ram:IssuerAssignedID>
  <ram:TypeCode>916</ram:TypeCode>
  <ram:Name>Timesheet March</ram:Name>
</ram:AdditionalReferencedDocument>

Related validation rules

• BR-01: Specification identifier (BT-24) is missing
• BR-02: Invoice number (BT-1) is missing
• BR-03: Invoice issue date (BT-2) is missing
• BR-04: Invoice type code (BT-3) is missing
• BR-05: Invoice currency code (BT-5) is missing
• BR-06: Seller name (BT-27) is missing