1. Conformity assessment—General requirements for the competence of proficiency testing providers, ISO/IEC 17043:2023.
2. General requirements for the competence of testing and calibration laboratories, ISO/IEC 17025:2017.
3. P9:06/2014 ILAC Policy for Participation in Proficiency Testing Activities.
4. P10:07/2020 ILAC Policy on Metrological Traceability of Measurement Results.
5. Guide to the expression of uncertainty in measurements, GUM, International Organisation for Standardization (ISO) (1995).