Books worth reading:
1) “Get Out of Your Mind and into Your Life: The New Acceptance and Commitment Therapy” by Steven Hayes (Professor of Psychology at the University of Nevada).
2) “The Worry Trap: How to Free Yourself from Worry and Anxiety Using Acceptance and Commitment Therapy” by Chad Lejeune (Clinical Psychologist).
3)”The Happiness Trap: Stop Struggling, Start Living” Dr. Russ Harris.
4)”Full Catastrophe Living” John Kabat-Zinn (Mndfulness Based Stress Reduction ,MBSR)
5) To get an excellent overview of how ACT and Mindfulness applies to anxiety related conditions you can read a few chapters from the book by Dr Georg H. Eifert and Dr John P. Forsyth:(The link takes you to Google book preview.)
Acceptance & commitment therapy for anxiety disorders
Research papers related to ACT and anxiety conditions: