1. American Psychiatric Association. 2000. Obsessive compulsive disorder. Diagnostic and Statistical Manual of Mental Disorders, 4th edition?Text revision. Washington, DC: APA Press. p 456-463.
2. Catechol-O-methyltransferase and Gilles de la Tourette syndrome
3. An association study between 5-HTTLPR polymorphism, COMT polymorphism, and Tourette's syndrome
4. 2000. Neuropsychiatric aspects of movement disorders. In: editors. Kaplan & Sadock's comprehensive textbook of psychiatry. Philadelphia: Lippincott Williams & Wilkins. p 285-289.