1) D.W. Sparkes: A Standard Choked Nozzle for Absolute Calibration of Air Flowmeters, The Aerona utical Journal of The Royal Aeronautical Society, 72, April, 335/338 (1968)
2) B.S. Stratford: The Calculation of the Discharge Coefficient of Profiled Choked Nozzles and the Opti mum Profile for Absolute Air Flow Measurement, Journal of the Royal Aeronautical Society, 68, April 237/245 (1964)