1. Verhulst F: Community and epidemiological aspects of anxiety disorders in children. In Anxiety Disorders in Children and Adolescents: Research, Assessment and Intervention. Edited by Silverman W, Treffers P. Cambridge: Cambridge University Press; 2001:273–292.
2. American Psychiatric Association: Diagnostic and Statistical Manual of Mental Disorders, edn 4, Text Revision. Washington, DC: American Psychiatric Association; 2000.
3. Gullone E: The development of normal fear: a century of research. Clin Psychol Rev 2000, 20:429–451.
4. Freeman J, Garcia A, Leonard H: Anxiety disorders. In Child and Adolescent Psychiatry: A Comprehensive Textbook. Edited by Lewis M. Philadelphia: Lippincott Williams & Wilkins; 2002:821–834.
5. Masi G, Mucci M, Millepiedi S: Separation anxiety disorder in children and adolescents: epidemiology, diagnosis and management. CNS Drugs 2001, 15:93–104.