# UBL-SR-18-SG

Source: https://xmlvalid.com/rules/UBL-SR-18-SG

> Buyer GST identifier shall occur maximum once

- Level: warning
- Rule sets: PINT SG rules (Singapore) 1.4.1
- Context: `/ubl:Invoice | /cn:CreditNote`
- Test: `(count(cac:AccountingCustomerParty/cac:Party/cac:PartyTaxScheme/cbc:CompanyID) <= 1)`

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