1. ISO 9300, Measurement of gas flow by means of critical flow Venturi nozzles,1990
2. Calibration of ultrasonic domestic gas meters;Bignell,1993
3. Intercomparison tests of gas flow rate standards;Takamoto,1993
4. Statistics for Physicists;Martin,1971
5. On the discharge coefficient of critical venturis;Watanabe;Bull. NRLM No. 41,1980