1. ISO/IEC Guide 43:1984,Development and Operation of laboratory proficiency testing, 1984.
2. ISO/IEC Guide 43:1997,Proficiency Testing by Interlaboratory Comparisons, 1997.
3. The international harmonized protocol for the proficiency testing of (chemical) analytical laboratories (Technical Report)
4. DIN EN ISO/IEC 17043,Conformity assessment – General requirements for proficiency testing, 2010.
5. ISO/IEC 17025,General requirements for the competence of testing and calibration laboratories, 2005.