Coffin, B. (1980). Coffin's overtones of bel canto: Phonetic basis of artistic singing with 100 chromatic vowel-chart exercises / by Berton Coffin. Scarecrow Press.
Chicago-viite (17. p.)Coffin, Berton. Coffin's Overtones of Bel Canto: Phonetic Basis of Artistic Singing with 100 Chromatic Vowel-chart Exercises / by Berton Coffin. Metuchen, N.J.: Scarecrow Press, 1980.
MLA-viite (8. p.)Coffin, Berton. Coffin's Overtones of Bel Canto: Phonetic Basis of Artistic Singing with 100 Chromatic Vowel-chart Exercises / by Berton Coffin. Scarecrow Press, 1980.
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