# PEPPOL-T16-B01701

Source: https://xmlvalid.com/rules/PEPPOL-T16-B01701

> Element 'cbc:URI' MUST be provided.

- Level: error
- Rule sets: Peppol Despatch Advice rules 3.5
- Context: `/ubl:DespatchAdvice/cac:AdditionalDocumentReference/cac:Attachment/cac:ExternalReference`
- Test: `cbc:URI`

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