1. Young, M.: Predicting ratings of severity of stuttering [monograph]. pp. 31–54 (1961)
2. Sherman, D.: Clinical and experimental use of the Iowa scale of severity of stuttering. J. Speech Hear. Disord. 17, 316–320 (1952)
3. Cullinan, W.L., Prathe, E.M., Williams, D.: Comparison of procedures for scaling severity of stuttering. J. Speech Hear. Res. 6, 187–194 (1963)
4. Bloodstein, O.: A handbook on stuttering. Singular Publishing Group Inc., San-Diego, London (1995)
5. Ravikumar, K.M., Rajagopal, R., Nagaraj, H.C.: An approach for objective assessment of stuttered speech using MFCC features. ICGST Int. J. Digital Sig. Proc. DSP 9, 19–24 (2009)