1. American Psychiatric Association. (1980). Diagnostic and statistical manual of mental disorders (3rd ed). Washington, DC: Author.
2. American Psychiatric Association. (1987). Diagnostic and statistical manual of mental disorders (3rd ed., rev.). Washington, DC: Author.
3. Beck, A.T. (1967). Depression: Clinical, experimental, and theoretical aspects. New York: Hoebner.
4. Beck, A.T. (1976). Cognitive theory and the emotional disorders. New York: International Universities Press.