Analysis of information sources in references of the Wikipedia article "Symphony No. 1 (Sibelius)" in English language version.
For example, in their 1987 book The Musician's Guide to Acoustics, Murray Campbell and Clive Greated note that the last movement of Jean Sibelius's Symphony No. 1 in E minor contains tones that lead to a rumbling IMD. The human ear processes sound in a nonlinear fashion, and so it can be "tricked" into hearing tones that weren't produced by the instruments and that aren't in the sheet music; those subliminal tones are produced when the played tones combine nonlinearly in the inner ear.
