Frederick, C., Hartman, W., Morton, P., Phillips, M., Watkins, J.G. & Wemple, J. (2002). A Celebration of the Life of Helen Huth Watkins. American Journal of Clinical Hypnosis, 45, 79-87.
Fritzsche, K. & Hartman, W. (2010). Einführung in die Ego-State-Therapie. Heidelberg: Carl-Auer-Systeme Verlag.
Guse, T., Wissing, M.P. & Hartman, W. (2006). The Effect of a Prenatal Hypnotherapeutic Programme on Postnatal Maternal Psychological Well-Being. Journal of Reproductive and Infant Psychology, 24, 2, 163-177.
Guse, T., Wissing, M.P. & Hartman, W. (2006). A Prenatal Hypnotherapeutic Program to Enhance Postnatal Psychological Wellbeing. Australian Journal of Clinical and Experimental Hypnosis, 34, 1, 27 - 40.
Hartman, W. (1988). Career Guidance with Urban Black Children. Master’s thesis in Educational Psychology. Rand Afrikaans University.
Hartman, W. (1994). Ego State Therapy with Sexually Traumatised Children. Doctoral dissertation. University of Pretoria.
Hartman, W. (1995a). Ego State Therapy with Sexually Traumatised Children. Pretoria: Kagiso Publishers.
Hartman, W. (1995b). Ego State Therapy with Sexually Traumatised Children. In G.D. Burrows & R. Stanley (Eds.), Contemporary International Hypnosis, Proceedings of the 13th International Congress of Hypnosis, Melbourne, Australia, August 6-12, 1994, (pp. 149-158). Chichester: John Wiley & Sons.
Hartman, W. (1995c). The Use of Ego State Therapy in the Treatment of Somatic Reactions to Trauma. Proceedings of the 1st Africa Congress in Clinical Hypnosis and Psychosomatic Medicine, Sun City, South Africa, October 15-19, 1995.
Hartman, W. (1998). Advanced Techniques of Ericksonian Utilization: The Use of Symptom Words, Figures of Speech and Sequences in Guiding Ego States’ Associations. Hypnos. Swedish Journal of Hypnosis in Psychotherapy and Psychosomatic Medicine, 24, 206-212.
Hartman, W. (2001). The Utilization of Ego State Patterns of Self- Expression in the Treatment of Aphonic Conversion Reactions. Hypnos. Swedish Journal of Hypnosis in Psychotherapy and Psychosomatic Medicine, XXVII, 4-10.
Hartman, W. (2002). Ego State Therapy - Then and Now: Towards a Naturalistic Utilization Approach. A Tribute to John. G. Watkins. Hypnos. Swedish Journal of Hypnosis in Psychotherapy and Psychosomatic Medicine, XXIX, 52-58.
Hartman, W. (2008). Mental Strengths and Experiential Solutions: Conquering the Trauma of Apartheid, Racism, Sexism and Xenophobia. HypnosNytt, 3, 7-16.
Hartman, W. (2009). Straight Guys with Queer Eyes: The Utilization of Opposing Ego States in the Treatment of Trauma-Related Sexual Orientation Distress. Tidsskrift for Klinisk Hypnose, 2, 13 - 22.
Hartman, W. (2009). Straight Guys with Queer Eyes: The Utilization of Opposing Ego States in the Treatment of Trauma-Related Sexual Orientation Distress. HypnosNytt. Swedish Journal of Clinical Hypnosis, 3, 3-13.
Hartman, W. (2010). Einführung in die Ego-State-Therapie. Heidelberg: Carl-Auer Verlag.
Hartman, W. (2012). Leave a trail of wisdom. A Tribute to John G Watkins Ph.D. Tidsskrift for Klinisk Hypnose, Nr 1, Maj 2012, 30.
Hartman, W. (2014). Over the Rainbow – Wie man farbenfrohe Lösungen entwickelt, um Ich-Zustände als Ressourcen glänzen zu lassen: Der Fall Esti. In: W. Brächter (Hrsg.), Der singende Pantomime: Ego-State-Therapie und Teilearbeit mit Kindern und Jugendlichen (pp. 212 - 226). Heidelberg, Germany: Carl-Auer Verlag.