APA (7th ed.) Citation
Asmundson, G. J. G., & Taylor, S. (2005). It's not all in your head: How worrying about your health could be making you sick--and what you can do about it. The Guilford Press.
Chicago Style (17th ed.) Citation
Asmundson, Gordon J. G., and Steven Taylor. It's Not All in Your Head: How Worrying About Your Health Could Be Making You Sick--and What You Can Do About It. New York: The Guilford Press, 2005.
MLA (9th ed.) Citation
Asmundson, Gordon J. G., and Steven Taylor. It's Not All in Your Head: How Worrying About Your Health Could Be Making You Sick--and What You Can Do About It. The Guilford Press, 2005.
Warning: These citations may not always be 100% accurate.