For the measure. Use UN/ECE Recommendation 20 and 21.subset.

Namespace
cbc urn:oasis:names:specification:ubl:schema:xsd:CommonBasicComponents-2
Data type
udt:MeasureType
Example value
123
Attributes
Use Name Description
M @unitCode

Measure unit of measure

Example value: MTR

Rules
Identifier/Error message Flag
PEPPOL-T125-B14501
Attribute 'unitCode' MUST be present.
fatal