1. Catatonia: a prospective clinical study;Abrams;Arch. Gen. Psychiatry,1976
2. Diagnostic and Statistical Manual of Mental Disorders;American Psychiatric Association,1980
3. Diagnostic and Statistical Manual of Mental Disorders;American Psychiatric Association,1987
4. Diagnostic and Statistical Manual of Mental Disorders;American Psychiatric Association,1994
5. On the methods and theory of reliability;Bartko;J. Nerv. Ment. Dis.,1976