# ibr-109

Source: https://xmlvalid.com/rules/ibr-109

> Referenced purchase order line identifier (ibt-132) MUST occur maximum once.

- Level: error
- Rule sets: PINT Billing rules 1.1.3, PINT Billing rules (as shipped with PINT AE) 1.0.4
- Context: `cac:InvoiceLine | cac:CreditNoteLine`
- Test: `(count(cac:OrderLineReference/cbc:LineID) <= 1)`

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