1. Formant frequency tuning in singing;Carlsson;J Voice,1992
2. Vowel modification revisited;Nix;J Sing,2004
3. What about the pure vowel and vowel modification?;Miller;J Sing,1995
4. The acoustics of the singing voice;Sundberg;Sci Am,1977
5. Speaking vowels versus singing vowels;Titze;J Sing,1995