<n0:ComplexDefinition xmlns:n0="http://ncicb.nci.nih.gov/xml/owl/EVS/ComplexProperties.xsd#"><n0:def-definition>A unit used for measuring substance concentration or/and activity as defined in the literature reference standard for the particular assay method.</n0:def-definition><n0:def-source>NCI</n0:def-source></n0:ComplexDefinition>