1. ISO, IEC 17025 (2005) General requirements for the competence of testing and calibration laboratories. International Standard Organization, Geneva
2. Water Framework Directive Chemical Monitoring Activity—EUR 22922 EN (2007) http://fate.jrc.ec.europa.eu/monitoring/activities/pdf-documentsWFD
3. Ramsey MH, Thompson M (2007) Uncertainty from sampling, in the context of fitness for purpose. Accred Qual Assur 12:503–513
4. ISO, IEC 17043 (2010) Conformity assessment general requirements for proficiency testing. International Standard Organization, Geneva
5. ISO 13528 (2005) Statistical methods for use in proficiency testing by interlaboratory comparisons. International standard Organization, Geneva