P. Zak et al., “Oxytocin Is Associated with Human Trustworthiness,” Horm Behav 48 (2005): 522; J. Holt-Lunstad et al., “Influence of a ‘Warm Touch’ Support Enhancement Intervention Among Married Couples on Ambulatory Blood Pressure, Oxytocin, Alpha Amylase, and Cortisol,” Psychosomatic Med 70 (2008): 976; V. Morhenn et al., “Monetary Sacrifice Among Strangers Is Mediated by Endogenous Oxytocin Release After Physical Contact,” EHB 29 (2008): 375; C. Crockford et al., “Urinary Oxytocin and Social Bonding in Related and Unrelated Wild Chimpanzees,” Proc Royal Soc B 280 (2013): 20122765.