If seller is icelandic and payment means code is 9 then a 12 digit account id must exist — Ef seljandi er íslenskur og greiðslumáti (BT-81) er krafa (kóti 9) þá skal koma fram 12 stafa númer (bankanúmer, höfuðbók 66 og reikningsnúmer) (BT-84)
ubl-creditnote:CreditNote[$SupplierCountry = 'IS'] | ubl-invoice:Invoice[$SupplierCountry = 'IS']exists(cac:PaymentMeans[cbc:PaymentMeansCode = '9']/cac:PayeeFinancialAccount/cbc:ID) and string-length(normalize-space(cac:PaymentMeans[cbc:PaymentMeansCode = '9']/cac:PayeeFinancialAccount/cbc:ID)) = 12 or not(exists(cac:PaymentMeans[cbc:PaymentMeansCode = '9']))