American Psychological Association. (2020). *Publication manual of the American Psychological Association* (7th ed.). https://doi.org/10.1037/0000165-000
Ashton, M. C. (2012). Biological bases of personality. In Individual differences and personality (2nd ed., pp. 101-121). Academic Press. https://doi.org/10.1016/B978-0-12-416009-5.00005-0