1. EN 45001, General Criteria for the Operation of Testing Laboratories, European Standardisation Committee, Brussels, 1989.
2. EN 45002, General Criteria for the Assessment of Testing Laboratories, European Standardisation Committee, Brussels, 1989.
3. EN 30011, Guidelines for Auditing Quality Systems, European Standardisation Committee, Brussels, 1989.
4. ISO/IEC Guide 25, General Requirements for the Competence of Calibration and Testing Laboratories, International Organization for Standardization, Geneva, 1990.
5. ISO/IEC Guide 30, Terms and Definitions Used in Connection with Reference Materials, International Organization for Standardization, Geneva, 1992.