1. American Association of Mental Deficiency. (1975). Adaptive Behavior Scale. Washington: Author.
2. American Psychiatric Association. (1987). Diagnostic and statistical manual of mental disorders (3rd ed. rev.). Washington: Author.
3. (1938). A visual motor gestalt test and its clinical use. New York: American Orthopsychiatric Association Research Monographs, No. 3.
4. (1975). Multivariate statistical methods in behavioral research. New York: Academic Press.