# ibr-co-19

Source: https://xmlvalid.com/rules/ibr-co-19

> If Invoicing period (ibg-14) is used, the Invoicing period start date (ibt-073) or the Invoicing period end date (ibt-074) MUST be filled, or both.

- Level: error
- Rule sets: PINT Billing rules 1.1.3, PINT Billing rules (as shipped with PINT AE) 1.0.4
- Context: `cac:InvoicePeriod`
- Test: `exists(cbc:StartDate) or exists(cbc:EndDate) or (exists(cbc:DescriptionCode) and not(exists(cbc:StartDate)) and not(exists(cbc:EndDate)))`

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