{
  "id": "UBL-SR-35",
  "country": "EU",
  "syntax": "ubl",
  "group": "syntax",
  "severity": "fatal",
  "severity_note": "fatal, from the Flag column of the Peppol BIS Billing 3.0 UBL rules index retrieved 2026-10-18.",
  "spec": "Peppol BIS Billing 3.0, May 2026 release, EN 16931 model bound to UBL",
  "statement": "Referenced purchase order line identifier shall occur maximum once",
  "statement_lang": "en",
  "context": "cac:InvoiceLine | cac:CreditNoteLine",
  "test": "(count(cac:OrderLineReference/cbc:LineID) <= 1)",
  "meaning": "The referenced purchase order line identifier shall occur at most once. The statement has no period and says shall. It is 66 characters. The flag is fatal. The context is an invoice line or a credit note line. The published test counts cac:OrderLineReference/cbc:LineID. The count comparison has a space before <= and a space after it.",
  "fix": "On an invoice line or a credit note line, send at most one referenced purchase order line identifier.",
  "example_fail": "An invoice line has two referenced purchase order line identifiers.",
  "example_pass": "An invoice line has one referenced purchase order line identifier, or none.",
  "example_note": "Illustration of the condition in the official statement. Not an example published by the source.",
  "source_url": "https://docs.peppol.eu/poacc/billing/3.0/rules/ubl-tc434/UBL-SR-35/",
  "source_retrieved": "2026-10-18",
  "last_verified": "2026-10-18"
}