1. Are there functional dysphonias?;Wendler,1997
2. J. Gonzalez, Fonación y alteraciones de la larynge. Edit. Panamericana, 1990.
3. La voz en la actividad docente;Dausserre;Fonoaudiológica,1983
4. Vocal profile and perceptual auditor and analysis of preschool teacher voices;Nagano,1998
5. Prevalence of voice disorders among future teachers;Simberg,1998