Girard-Buttoz, C., Heistermann, M., Krummel, S., & Engelhardt, A. (2009). Seasonal
and social influences on fecal androgen and glucocorticoid excretion in wild male long-tailed macaques (Macaca fascicularis). Physiology & Behavior, 98(1-2), 168-175. doi:10.1016/j.physbeh.2009.05.005.