1-Niebudek-Bogusz E, Koty1o P, Sliwi_nska-Kowalska M. Evaluation of voice acoustic parameters related to the vocal-loading test in professionally active teachers with dysphonia. Int J Occup Med Environ Health. 2007;20:25–30.
2-Titze IR, Lemke J, Montequin D. Populations in the U.S. workforce who rely on voice as a primary tool of trade: a preliminary report. J Voice. 1997;11:254–259.
3-Roy N, Merrill RM, Thibeault S, Parsa R, Gray SD, Smith EM. Prevalence of voice disorders in teachers and general population. J Speech Lang Hear Res. 2004;47:281–293.
4-Roy N, Merrill RM, Thibeault S, Gray SD, Smith EM. Voice disorders in teachers and the general population: effects on work performance, attendance, and future career choices. J Speech Lang Hear Res. 2004;47: 542–551.
5-Smith E, Gray S, Dove H, Kirchner L, Heras H. Frequency and effects of teachers’ voice problems. J Voice. 1997;11:81–87.
6-Rantala L,Vilkman E. Relationship between subjective voice complaints and acoustic parameters in female teachers’ voices. J Voice. 1999;13:484–495.
7-Eustace C, Stemple J, Lee L. Objective measures of voice production in patients complaining of laryngeal fatigue. J Voice. 1996;10:146–154.
8-Gelfer MP, Andrews ML, Schmidt CP. Documenting laryngeal change following prolonged loud reading. A videostroboscopic study. J Voice. 1996;10:368–377.
9-Stemple JC, Stanley J, Lee L. Objective measures of voice production in normal subjects following prolonged voice use. J Voice. 1995;9:127–133.
10-Vilkman E, Lauri ER, Alku P, Sala E, Sihvo M. Effects of prolonged oral reading on F0, SPL, subglottal pressure and amplitude characteristics of glottal flow waveforms. J Voice. 1999;13:303–312.
11-Gelfer MP, Andrews M, Schmidt C. Effects of prolonged loud reading on selected measures of vocal function in trained and untrained singers. J Voice. 1991;5:158–167.
12-Rajasudhakar R, Savithri SR. Voicing periods in a primary school teacher. JAIISH. 2009;28:36–41.
13-Muller C. Speaker Classification: Fundamentals, Features, and Methods. New York, NY: Springer; 2007.
14-Bonetti L, Bonetti A, Bolfan-Stosic N. Harmonics to noise ratio in vocal professional voices. J Acoust Soc Am. 2002;111:2480–2481.
15-Hirano M. Clinical Examination of Voice. New York, NY: Springer-Verlag; 1981:83–84.
16-Paul B, Weenink D. Praat: doing phonetics by computer [Computer program]. Available at:
http://www.praat.org/.
17-Parsa V, Jamieson DG. Acoustic discrimination of pathological voice: sustained vowels versus continuous speech. J Speech Lang Hear Res. 2001;44: 327–339.
18-Scherer RC, Vail VJ, Guo CG. Required number of tokens to determine representative voice perturbation values. J Speech Lang Hear Res. 1995;38:1260–1269.
19-Williams J. Vocal Health for children and adults. Available at:
http://www. jenevorawilliams.com/.
20-Preciado J, P_erez C, Calzada M, Preciado P. Function vocal examination and acoustic analysis of 905 teaching staff of La Rioja, Spain. Acta Otorrinolaringol Esp. 2005;56:261–272.
21-Butler JE, Hammond TH, Gray SD. Gender-related differences of hyaluronic acid distribution in the human vocal fold. Laryngoscope. 2001;111: 907–911.
22-Rantala L, Vilkman E, Bloigu R. Voice changes during work: subjective voice complaints and objective measurements for female primary and secondary school teachers. J Voice. 2002;16:344–355.
23-Rajasudhakar R, Savithri SR. Effects of teaching and voice rest on acoustic voice characteristics of female primary school teachers. JAIISH. 2010;29: 198–203.
24-Titze IR. Vocal fold mass is not a useful quantity for describing F0 in vocalization. J Speech Lang Hear Res. 2011;54:520–522.
25-Laukkanen AM, Ilom€aki I, Lepp€anen K, Vilkman E. Acoustic measures and self-reports of vocal fatigue by female teachers. J Voice. 2008;22:283–289.
26-Yumoto E, Sasaki Y, Okamura H. Harmonics-to-noise ratio and psychophysical measurement of the degree of hoarseness. J Speech Hear Res.1984;27:2–6.