R. Sjoberg et al., “A Non-additive Interaction of a Functional MAO-A VNTR and Testosterone Predicts Antisocial Behavior,” Neuropsychopharmacology 33 (2008): 425; R. McDermott et al., “Monoamine Oxidase A Gene (MAOA) Predicts Behavioral Aggression Following Provocation,” PNAS 106 (2009): 2118; D. Gallardo-Pujol et al., “MAOA Genotype, Social Exclusion and Aggression: An Experimental Test of a Gene-Environment Interaction,” Genes, Brain and Behav 12 (2013): 140; A. Reif et al., “Nature and Nurture Predispose to Violent Behavior: Serotonergic Genes and Adverse Childhood Environment,” Neuropsychopharmacology 32 (2007): 2375.