If seller and buyer are icelandic then the invoice shall contain the buyers address with street name and zip code — Ef seljandi og kaupandi eru íslenskir þá skal heimilisfang kaupanda innihalda götuheiti og póstnúmer (BT-50 og BT-53)
ubl-creditnote:CreditNote[$SupplierCountry = 'IS' and $CustomerCountry = 'IS']/cac:AccountingCustomerParty | ubl-invoice:Invoice[$SupplierCountry = 'IS' and $CustomerCountry = 'IS']/cac:AccountingCustomerPartyexists(cac:Party/cac:PostalAddress/cbc:StreetName) and exists(cac:Party/cac:PostalAddress/cbc:PostalZone)