1. Wolberg, L. R.: Principles of Hypnotherapy. Vol. 1, p. 345. Grune & Stratton. New York. 1948.
2. Erickson, M. H.: The applications of hypnosis to psychiatry. Med. Rec., 60–65, July 19, 1939.
3. Brenman, M., and Gill, M. M.: Hypnotherapy: A Survey of the Literature. International Universities Press. New York. 1947.
4. Copeland, C. L., and Kitching, H. E.: Hypnosis in mental hospital practice. J. Ment. Sci., 328, 1937.
5. Bleuler, E.: Textbook of Psychiatry. Macmillan. New York. 1924.