S. Levine et al., “The PNE of Stress: A Psychobiological Perspective,” in Psychoneuroendocrinology, ed. S. Levine and R. Brush (New York: Academic Press, 1988), p. 181; R. Sapolsky and J. Ray, “Styles of Dominance and Their Physiological Correlates Among Wild Baboons,” Am J Primat l8 (1989): l; J. C. Ray and R. Sapolsky, “Styles of Male Social Behavior and Their Endocrine Correlates Among High-Ranking Baboons,” Am J Primat 28 (1992): 231; C. E. Virgin and R. Sapolsky, “Styles of Male Social Behavior and Their Endocrine Correlates Among Low-Ranking Baboons,” Am J Primat 42 (1997): 25.