G. M. Alexander and M. Hines, “Sex Differences in Response to Children’s Toys in Nonhuman Primates (Cercopithecus aethiops sabaeus),” EHB 23 (2002): 467 (рисунок в тексте из этого источника). J. M. Hassett et al., “Sex Differences in Rhesus Monkey Toy Preferences Parallel Those of Children,” Horm Behav 54 (2008): 359.
