1. EN 1434-97, Heat Meters. Part 1. General Requirements.
2. GOST 8.563.2-97, GSI. Measurement of Flow Rate and the Amount of Liquids and Gases by the Variable Pressure Drop Method. Measurement Procedure by Means of Constriction Devices.
3. G. A. Neiman, Ya. G. Fudim, and V. A. Medvedev, Énergosberezh., No. 5, 24 (2002).