1. American Psychiatric Association: Diagnostic and Statistical Manual of Mental Disorders, ed 4, Text Revision (DSM-IV-TR). Washington, American Psychiatric Association, 2000.
2. World Health Organization: The ICD-10 classification of mental and behavioural disorders. Geneva, World Health Organization, 1992.
3. Kraepelin E: Manic-Depressive Insanity and Paranoia. Edinburgh, Livingstone E & S, 1921.
4. Leonhard K: The Classification of Endogenous Psychoses. New York, Irvington, 1979.