# BR-52

Quoted from a public specification. This page is not a validator, and it is not tax, legal, or accounting advice.

- Country: EU
- Syntax: UBL
- Severity: fatal
- Statement language: en
- Last verified: 2026-10-18

## Official statement

> Each Additional supporting document (BG-24) shall contain a Supporting document reference (BT-122).

Source: https://docs.peppol.eu/poacc/billing/3.0/rules/ubl-tc434/BR-52/

Peppol BIS Billing 3.0, May 2026 release, EN 16931 model bound to UBL

Severity note: fatal, from the Flag column of the Peppol BIS Billing 3.0 UBL rules index retrieved 2026-10-18.

## Plain-language reading

Each Additional supporting document (BG-24) must contain a Supporting document reference (BT-122). The message says "shall contain", not "shall contain the", and it starts with "Each". It ends with a period. The context is an additional document reference. The published test checks that cbc:ID is not blank. The comparison is != '' with a space.

## What to change

Put a non-blank supporting document reference (BT-122) on each additional supporting document.

## Illustration

Illustration of the condition in the official statement. Not an example published by the source.

**Fails the stated condition.** An additional document reference has no identifier, or that identifier is blank.

**Passes the stated condition.** That document reference identifier contains a non-empty value.

## Published context and test

Copied from the source. Not reimplemented on this page.

```
cac:AdditionalDocumentReference
```

```
normalize-space(cbc:ID) != ''
```

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