The seller's identity on the item.

Namespace
cbc urn:oasis:names:specification:ubl:schema:xsd:CommonBasicComponents-2
Data type
udt:IdentifierType
Example value
17589683
Rules
Identifier/Error message Flag
PEPPOL-T128-R003
Each item in a Receipt Advice line SHALL be identifiable by either "item seller's identifier" or "item standard identifier"
fatal