1. ISO, IEC 17025 (2005) General requirements for the competence of testing and calibration laboratories. International Organization for Standardization/International Electrotechnical Commission, Geneva
2. EA-4/18 (2010) Guidance on the level and frequency of proficiency testing participation. http://www.european-accreditation.org/publication/ea-4-18-inf-rev00-june-2010
3. ISO, IEC 17043 (2010) Conformity assessment—general requirements for proficiency testing. International Organization for Standardization/International Electrotechnical Commission, Geneva
4. ISO 13528 (2005) Statistical methods for use In proficiency testing by interlaboratory comparisons. International Organization for Standardization, Geneva
5. Kuselman I, Fajgelj A (2010) IUPAC/CITAC Guide: Selection and use of proficiency testing schemes for limited number of participants- chemical analytical laboratories (IUPAC Technical Report). Pure Appl Chem 82(5):1099–1135