Message SAP WRF_REF018 - &4 Mat. &1 not listed in plant &2 in the last &3 week(s) nor in future DOCUMENTATION DiagnosisThe system has carried out the listing check for reference &V1&/&V2&.The material &V1& in plant &V2& is not listed in the last &V3& week(s)nor in future.System ResponseThe system does not assign this combination as a reference.