John, O. P., Naumann, L. P., & Soto, C. J. (2008). Paradigm shift to the integrative big five trait taxonomy. Handbook of personality: Theory and research, 3(2), 114-158.
Allport, G. W., & Odbert, H. S. (1936). Trait-names: A psycho-lexical study. Psychological monographs, 47(1), i.
Cattell, R. B. (1943). The description of personality: Basic traits resolved into clusters. The journal of abnormal and social psychology, 38(4), 476.