1. Downton W. The effect of attitude on the speech breathing of stutterers. M.A. thesis University of Iowa 1934.
2. Disturbances in breathing during stuttering;Fossler H. R;Psych. Monog.,1930
3. A study of breathing and vocal disturbances of stutterers. Arch. of Speech;Henrikson E. H;Studies in Speech Pathology,1936
4. Travis L. E. Speech Pathology. D. Appleton Co. New York 1931.
5. A study of the horizontal dysintegration of breathing during stuttering. Arch. of Speech;Travis V. E;Studies in Speech Pathology,1936