# HR-BR-6

Source: https://xmlvalid.com/rules/HR-BR-6

> Svaka referenca prethodnog računa (BG-3) mora imati datum izdavanja prethodnog računa (BT-26)

- Level: error
- Rule sets: Croatian eRačun rules (UBL) 13.03.2026
- Context: `cac:BillingReference`
- Test: `exists(cac:InvoiceDocumentReference/cbc:ID) and exists(cac:InvoiceDocumentReference/cbc:IssueDate)`

In English: Each preceding invoice reference (BG-3) must have the preceding invoice's issue date (BT-26).

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