1. ISO 5725-1/6 Accuracy (trueness and precision) of measurement methods and results, International Organization for Standardization, Geneva
2. ISO Guide 43-1/2 (1997) Proficiency testing by interlaboratory comparisons, International Organization for Standardization, Geneva
3. ISO 17025 (2004) General requirements for the competence of testing and calibration laboratories, International Organization for Standardization, Geneva
4. ISO (1995) Guide to the expression of uncertainty in measurement, GUM International Organization for Standardization, Geneva
5. ISO 13528 (2005) Statistical methods for use in proficiency testing by interlaboratory comparisons, International Organization for Standardization, Geneva