1. Voluntary Movements of the Organs of Speech in Stutterers and Non-Stutterers;Blackburn B;Psych. Monog.,1931
2. Measuring Motor Ability. A. S. Barnes and Co;Brace D. K;New York,1927
3. An Experimental Study of Stuttering;Fletcher John M;Am. Jour. of Psychol.,1914
4. The Effect of Stuttering on Voluntary Movement;Herren R. Y;Jour. of Exper. Psychol.,1931
5. McCloy C. H. Tests and Measurements in Physical Education. F. S. Crofts and Co. 1939 New York p. 57.