1. APA. (2013). Diagnostic and statistical manual of mental disorders: DSM-V (5th ed.). Arlington: American Psychiatric Association.
2. Beavan, V., Read, J., & Cartwright, C. (2011). The prevalence of voice-hearers in the general population: A literature review. Journal of Mental Health, 20(3), 281–292.
3. Benner, D. G. (1989). Toward a psychology of spirituality: Implications for personality and psychotherapy. Journal of Psychology and Christianity, 5, 19–30.
4. Blass, R. B. (2006). Beyond illusion: Psychoanalysis and the question of religious truth. In D. Birksted-Breen (Gen. Ed.), & D. M. Black (Ed.), Psychoanalysis and religion in the 21st century: Competitors or collaborators? (pp. 23–43). London: Routledge.
5. Boisen, A. T. (1936). The exploration of the inner world: A study of mental disorder and religious experience. Philadelphia: University of Pennsylvania Press.