1. Maddi, S.R. 2001. Personality Theories: A Comparative Analysis, 6th ed. Waveland Press Inc, Long Grove, IL, USA.
2. An alternative ‘description of personality’: The big-five factor structure. Personality and Personality Disorders, Sci;Goldberg L.R.;Mental Health,2013
3. The Enneagram: A Review of the Empirical and Transformational Literature
4. The Diagnostic Interview Schedule for Children-Revised Version (DISC-R): I. Preparation, Field Testing, Interrater Reliability, and Acceptability
5. Validity and Reliability of the Myers-Briggs Personality Type Indicator: A Systematic Review and Meta-analysis;Ken R.;Journal of Best Practices in Health Professions Diversity, 10 (1),2017