£The precision
statistics were determined through statistical examination of 136 results, from eight laboratories, on six materials.
The six materials were identified as:
£Pure Copper: NCS NS4 1004
£Phosphorus-deoxidized Copper: BCR
No 18 CRM
£Continuous cast copper rod: BCR
No 58 CRM
£OFHC Copper: Internal Standard
£ETP Copper: BCR No 22 CRM
£Refined copper; Check Standard: NIST
SRM 885
£