Zug, Robert M. (1893). A study of the number of children with speech disorders in the Boston Public Schools.

Conradi, E. (1904). Psychology and pathology of speech development in the child. Pedagogical Seminary, 11, 327-380. A study of the incidence of speech disorders in children in the Kansas City, Milwaukee, Cleveland, Louisville, Albany & Springfield Schools.

Ferreri, Guilio (1911). Defects of speech among primary pupils. Volta Review, 8, 31-33. A study of students in New York City. 200,000 of 800,000 children are affected with stuttering and speech defects.

Wallin, J. E. W. (1915-16). Report on speech defectives in the St. Louis Public Schools. St. Louis: Annual Report of the Board of Education. A study of 89,045 students in St. Louis Public Schools. (Reprinted in School and Society, 3, 213-216 and in a book published by Miami University in 1926: Speech defective children in a large school system. Oxford Ohio: Miami University.)

Blanton, Smiley (1916). A survey of speech defects: Madison Wisconsin Public Schools. Journal of Educational Psychology, 7, 581-592. A study of 5,000 public school children in Madison, Wisconsin.

Brown, Grace (1916). Report of corrective speech work in the Rochester Public Schools. Volta Review, 18, 143-144.

Camp, P. (1921). Speech treatment in the schools of Grand Rapids: A report of cases. Quarterly Journal of Speech Education, 7, 120-138.

Camp, P. (1923). Speech correction in the Wisconsin Public Schools. Quarterly Journal of Speech Education, 9, 280-283

Stinchfield, Sara (1925). The speech of five hundred freshman college women. Journal of Applied Psychology, 9, 109-121.

Hawk, Sara Stinchfield. Report on a study of speech problems at Mount Holyoke College. American Speech, 2, 148-152.