# IS-R-004

Source: https://xmlvalid.com/rules/IS-R-004

> If seller and buyer are icelandic then the invoice shall contain the buyers icelandic legal identifier — Ef seljandi og kaupandi eru íslenskir þá skal reikningurinn innihalda íslenska kennitölu kaupanda (BT-47).

- Level: error
- Rule sets: Peppol BIS Billing 3.0 rules 3.0.21
- Context: `ubl-creditnote:CreditNote[$SupplierCountry = 'IS' and $CustomerCountry = 'IS']/cac:AccountingCustomerParty | ubl-invoice:Invoice[$SupplierCountry = 'IS' and $CustomerCountry = 'IS']/cac:AccountingCustomerParty`
- Test: `exists(cac:Party/cac:PartyLegalEntity/cbc:CompanyID) and cac:Party/cac:PartyLegalEntity/cbc:CompanyID/@schemeID = '0196'`

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