DIN 45640-2
DIN 45640-2 Noise emitted by vessels on inland water-ways and harbours; enveloping surface method for the determination of the sound power level
standard by Deutsches Institut Fur Normung E.V. (German National Standard), 11/01/1993
standard by Deutsches Institut Fur Normung E.V. (German National Standard), 11/01/1993