Acoustics - Reference zero for the calibration of audiometric equipment - Part 4: Reference levels for narrow-band masking noise (ISO 389-4:1994); German version EN ISO 389-4:1998
German title
Akustik - Standard-Bezugspegel für die Kalibrierung audiometrischer Geräte - Teil 4: Bezugspegel für schmalbandige Verdeckungsgeräusche (ISO 389-4:1994); Deutsche Fassung EN ISO 389-4:1998
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