John, O.P. & Srivastava, S. (1999) ‘The Big Five Trait Taxonomy: History, Measurement, and Theoretical Perspectives’, in L.A. Pervin and O.P. John (eds) Handbook of Personality: Theory and Research, 2nd edn, pp. 102–38. New York: Guilford. http://moityca.com.br/pdfs/bigfive_John.pdf