# ibr-052

Source: https://xmlvalid.com/rules/ibr-052

> Each Additional supporting document (ibg-24) MUST contain a Supporting document reference (ibt-122).   

- Level: error
- Rule sets: PINT Billing rules 1.1.3, PINT Billing rules (as shipped with PINT AE) 1.0.4
- Context: `cac:AdditionalDocumentReference`
- Test: `(normalize-space(cbc:ID)) != ''`

Validate a document against these rules: https://xmlvalid.com/validate