1) ISO 7029 (Second edition), Acoustics — Statistical distribution of hearing thresholds as a function of age (International Organization for Standardization, Geneva, 2000).
2) D. W. Robinson and G. J. Sutton, A comparative analysis of data on the relation of pure-tone audiometric thresholds to age, NPL Acoustics Report AC 84 (National Physical Laboratory, Teddington, 1978).
3) M. S. Shipton, Tables relating pure-tone audiometric threshold to age, NPL Acoustics Report AC 94 (National Physical Laboratory, Teddington, 1979).
5) N. Kiritani, H. Inoue, Y. Asano, H. Seki, Y. Honda, Y. Ikeda and K. Doumitsu, “Evaluation of age classified adult hearing level tested by the new JIS standard audiometer —Mean, standard deviation, mode and median—,” Oto-Rhino-Laryngology, 35, 221–228 (1992).