1. American Psychiatric Association. (2000). Diagnostic and statistical manual of mental disorders – Fourth edition text revision (DSM-IV-TR). Washington, DC: American Psychiatric Association.
2. Barkham, M., Evans, C., Margison, F., McGrath, G., Mellor-Clark, J., Milne, D., et al. (1998). The rationale for developing and implementing core batteries in service settings and psychotherapy outcome research. Journal of Mental Health, 7, 35–47.
3. Birtchnell, J. (1993/1996). How Humans Relate: A New Interpersonal Theory. Hardback (1993): Westport, CN.: Praeger; paperback (1996): Hove, UK: Psychology Press.
4. Birtchnell, J. (1994). The interpersonal octagon: An alternative to the interpersonal circle. Human Relations, 47, 518–524.
5. Birtchnell, J., Hammond, S., Horn, E., De Jong, C., & Kalaitzaki, A. (2013). A cross-national comparison of a shorter version of the Person’s Relating to Others Questionnaire. Clinical Psychology and Psychotherapy, 20(1), 36–48.