The lists of valid countries are registered with the ISO 3166-1 Maintenance agency, "Codes for the representation of names of countries and their subdivisions". It is recommended to use the alpha-2 representation.

Namespace
cbc urn:oasis:names:specification:ubl:schema:xsd:CommonBasicComponents-2
Example value
NO
Code lists
Country codes (ISO 3166-1:Alpha2)
Attributes
Use Name Description
O @listID

Code list identifier

Fixed value: ISO3166-1:Alpha2

Rules
Identifier/Error message Flag
EUGEN-T68-B14301
Value MUST be part of code list 'Country codes (ISO 3166-1:Alpha2)'.
fatal
EUGEN-T68-B14303
Document MUST NOT contain elements not part of the data model.
fatal