Ultrasonic power measurement in liquids in the frequency range 0,5 MHz to 25 MHz (IEC 61161:1992 + A1:1998); German version EN 61161:1994 + A1:1998— 18 стр.
The absolute calibration of hydrophones using the planar scanning technique in the frequency range 0,5 MHz to 15 MHz (IEC 61101:1991); German version EN 61101:1993— 15 стр.