1. af Klint, Hilma. 2005. Excerpts from Notes by Hilma af Klint. Edited by Gurli Lindén. In Hilma af Klint, ed. John Hutchinson, 46–47; 64–65. Dublin: The Douglas Hyde Gallery.
2. Houghton, Georgiana. 1871. Catalogue of the Spirit Drawings in Water Colours, Exhibited at the New British Gallery, Old Bond Street. By Miss Houghton, through Whose Mediumship They Have Been Executed. London: W. Corby.
3. ———. 1881. Evenings at Home in Spiritual Séance, Prefaced and Welded Together by a Species of Autobiography. First series. London: Trübner & Co.
4. ———. 1882. Evenings at Home in Spiritual Séance, Welded Together by a Species of Autobiography. Second series. London: E. W. Allen.
5. Jung, Carl Gustav. 2009. The Red Book. Liber Novus. Edited by Sonu Shamdasani. London and New York: Philemon Foundation/W. W. Norton & Co.