# GR-S-011

Source: https://xmlvalid.com/rules/GR-S-011

> Greek suppliers must provide their Seller Tax Registration Number, prefixed by the country code

- Level: warning
- Rule sets: Peppol BIS Billing 3.0 rules 3.0.21
- Context: `cac:AccountingSupplierParty[$isGreekSender]/cac:Party`
- Test: `count(cac:PartyTaxScheme[normalize-space(cac:TaxScheme/cbc:ID) = 'VAT']/cbc:CompanyID)=1 and substring(cac:PartyTaxScheme[normalize-space(cac:TaxScheme/cbc:ID) = 'VAT']/cbc:CompanyID,1,2) = 'EL' and u:TinVerification(substring(cac:PartyTaxScheme[normalize-space(cac:TaxScheme/cbc:ID) = 'VAT']/cbc:CompanyID,3))`

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