1. ISO (1997) ISO/IEC guides 43-1 and 43-2: proficiency testing by interlaboratory comparisons, Part 1 and Part 2. International Organization for Standardization, Geneva
2. ILAC (2007) ILAC G13: guidelines for the requirements for the competence of providers of proficiency testing schemes. International Laboratory Accreditation Cooperation, Sydney
3. Thompson M, Ellison SLR, Wood R (2006) The international harmonised protocol for the proficiency testing of analytical chemistry laboratories. Pure Appl Chem 78(1):145–196. doi: 10.1351/pac200678010145
4. ISO (2005) ISO/IEC 17025: general requirements for the competence of calibration and testing laboratories. International Organization for Standardization, Geneva
5. ISO (2005) ISO 13528: statistical methods for use in proficiency testing by interlaboratory comparison. International Organization for Standardization, Geneva