1. On the sensations of tone as physiological basis for the theory of music;Helmholtz,1877
2. L. Rayleigh, 1877, The Theory of Sound, Vol. 1, Dover, New York, 1945, pp.46–51 (reprinted).
3. H. Lorenz, Lehrbuch der Technischen Physik. Technische Mechanik Starrer Gebilde, Erster Band. Verlag von Julius Springer, Berlin, 1924.
4. Engineering Vibrations;Jacobsen,1958
5. A. Watari, Kikai-rikigaku, Kyouritsu (publisher), 1969.