Arpi Minassian, PhD, Mark A. Geyer, PhD, Dewleen G. Baker, MD, Caroline M. Nievergelt, PhD, Daniel T. O'Connor, MD, Victoria B. Risbrough, PhD, and the Marine Resiliency Study Team, "Heart Rate Variability in a Large Group of Active-Duty Marines and Relationship to Posttraumatic Stress," Psychosomatic Medicine 76, no. 4 (May 2