[1] International Standardization Organization, “ISO 226: 2003(E): Acoustics—Normal Equal-Loudness-Level Contours,” Geneva, Switzerland.
[2] J. Parmanen, “A-Weighted Sound Pressure Level as a Loudness/Annoyance Indicator for Environmental Sounds— Could It Be Improved?” Applied Acoustics, Vol. 68, No. 1, 2007, pp. 58-70. doi:10.1016/j.apacoust.2006.02.004
[3] J. Parmanen, “Erratum: A-Weighted Sound Pressure Level as a Loudness/Annoyance Indicator for Environmental Sounds—Could It Be Improved? [Applied Acoustics, 68 (2007) 58-70],” Applied Acoustics, Vol. 69, No. 2, 2008, p. 183. doi:10.1016/j.apacoust.2006.09.006
[4] Y. Suzuki and H. Takeshima, “Equal-Loudness-Level Contours for Pure Tones,” Journal of the Acoustical Society of America, Vol. 116, No. 2, 2004, pp. 918-933. doi:10.1121/1.1763601
[5] International Standardization Or-ganization, “ISO 226:1987 (E): Acoustics—Normal Equal-Loudness-Level Contours,” Geneva, Switzer-land.
[6] International Standardization Organization, “ISO 532:1975 (E): Acoustics—Method For Calculating Loudness Level,” Geneva, Switzerland.