If seller is icelandic then invoice type should be 380 or 381 — Ef seljandi er íslenskur þá ætti gerð reiknings (BT-3) að vera sölureikningur (380) eða kreditreikningur (381).
ubl-creditnote:CreditNote[$SupplierCountry = 'IS'] | ubl-invoice:Invoice[$SupplierCountry = 'IS']
( ( not(contains(normalize-space(cbc:InvoiceTypeCode),' ')) and contains( ' 380 381 ',concat(' ',normalize-space(cbc:InvoiceTypeCode),' ') ) ) ) or ( ( not(contains(normalize-space(cbc:CreditNoteTypeCode),' ')) and contains( ' 380 381 ',concat(' ',normalize-space(cbc:CreditNoteTypeCode),' ') ) ) )