1. ISO Guide 43–1 (1997) Proficiency testing by interlaboratory comparisons Part 1: Development and operation of proficiency testing schemes. International Standardisation Organisation, Geneva, Switzerland
2. ISO 13528 (2000) (working document) Statistical methods for use in proficiency testing by interlaboratory comparisons. International Standardisation Organisation, Geneva, Switzerland
3. Gy P (1988) Hétérogénéité Echantillonnage Homogénéisation. Masson, Paris
4. Van der Veen AMH, Pauwels J (2000) Accred Qual Assur 5:464–469
5. Linsinger T, Pauwels J, Van der Veen AMH, Schimmel H, Lamberty A (2001) Accred Qual Assur 6:20–25