Allport, G. W. (1961). Pattern and growth in personality. New York: Holt, Rinehart and Winston.
Clark L. A., Watson D. (1991) Tripartite model of anxiety and depression: Psychometric evidence and taxonomic implications. Journal of Abnormal Psychology; p336.
Day, D.V., Bedeian, A.G. & Conte, J.M. (1998). Personality as predictor of work-related outcomes: Test of a mediated latent structural model. Journal of Applied Social Psychology, vol. 28, pp. 2068-2088.