Reference
- ISO Technical Committee 43-Acoustics, No. 554: A Standard Reference Zero for the Calibration of Pure Tone Audiometers. , N. Y : American Standards Association . 10 East 40th Street New York 16
- 1958 . Committee on Medical Rating or Physical Impairment: Guides to the Evaluation of Permanent Impairment. . J. Amer. Med. Assoc. , 168 : 475