1. Word Gas Meter Report, 6th edition, 2007, ABS Energy Research, London.
2. Opportunities and future trends in legal metrology control of measuring instruments;Chappell;OIML Bulletin,2004
3. The relationship between calibration, verification and metrological confirmation;Runsheng;OIML Bulletin,2004
4. ISO 10012:2003 Measurement Management Systems – Requirements for Measurement Processes and Measuring Equipment.
5. OIML 2000, International Vocabulary of Terms in Legal Metrology: VIML 2.13.