TY  - RPRT
TI  - Primary reference materials for chemical composition analysis - Proposal for an operational definition.
AU  - W Hässelbarth
PY  - 1996
DO  - 10.1007/s0021663540263
UR  - https://pubmed.ncbi.nlm.nih.gov/15048445/
ID  - 15048445
ER  -