1. D.D. Durrell, Durrell Analysis of Reading Difficulty (New York: Harcourt, Brace and World, 1955)
2. A. Gates, Improvement of Reading: A Program of Diagnostic and Remedial Methods (New York : Macmillan, 1947): 626.
3. B.H. Slingerland, Screening Tests for Identifying Children with Specific Language Disability (Cambridge, Massachusetts: Educators Publishing Service, 1970): 3-4.