1. Alpern G. D., Boll T. J., Shearer M. S., (1980). Developmental Profile II. Psychological Development Publications, Aspen, CO
2. American Psychiatric Association, (1980). Diagnostic and statistical manual of mental disorders. (3). Author, Washington, DC
3. American Psychiatric Association, (1987). Diagnostic and statistical manual of mental disorders (3rd ed. revised). Washington, DC: Author
4. American Psychiatric Association, (1994). Diagnostic and statistical manual of mental disorders. (4). Author, Washington, DC
5. Bayley N., (1993). Bayley Scales of Infant Development. (2) Psychological Corporation, San Antonio, TX