Huppert JD, Cahill SP, Foa EB. Anxiety Disorders: Cognitive–Behavioral Therapy. In: B. J. Sadock, V. A. Sadock, & Ruiz, P. (Eds.), Kaplan & Sadock’s Comprehensive Textbook of Psychiatry (9th edition). Philadelphia, PA: Lippincott, Williams, & Wilkins ; 2009.