1. 1) T. Chiba and M. Kajiyama, The Vowel: Its Nature and Structure (Tokyo-Kaiseikan Pub. Co., Ltd., Tokyo, 1941), pp. 115-154.
2. 2) K. Maekawa, ``From articulatory phonetics to the physics of speech: Contribution of Chiba and Kajiyama,'' Acoust. Sci. & Tech., 23, 185-188 (2002).
3. 3) G. Fant, Acoustic Theory of Speech Production (Mouton, The Hague, 1960).
4. 4) K. N. Stevens, Acoustic Phonetics (MIT Press, Cambridge, MA, 1998).
5. 5) J. L. Flanagan, Speech Analysis, Synthesis and Perception (Springer-Verlag, Berlin, 1965).