Otto Rank. The Double: A Psychoanalytic Study. 1925 (written 1914). （英文）
Rodney Davies. (2001). Doubles: The Enigma of the Second Self. Robert Hale Ltd. ISBN 978-0709061182（英文）
Gerald Bär: Das Motiv des Doppelgängers als Spaltungsphantasie in der Literatur und im deutschen Stummfilm. Editions Rodopi, Amsterdam / New York, NY 2005, ISBN 978-90-420-1874-7. （德文）
Ingrid Fichtner (Hrsg.): Doppelgänger. Von endlosen Spielarten eines Phänomens. Haupt, Bern / Stuttgart / Wien 1999, ISBN 3-258-06000-2 (= Facetten der Literatur, Band 7). （德文）
Christof Forderer: Ich-Eklipsen. Doppelgänger in der Literatur seit 1800. Metzler, Stuttgart / Weimar 1999, ISBN 3-476-45209-3. （德文）
Brugger, P; Regard, M; Landis, T. (1996). Unilaterally Felt 『『Presences』』: The Neuropsychiatry of One’s Invisible Doppelgänger. Neuropsychiatry, Neuropsychology, and Behavioral Neurology 9: 114-122.
Keppler, C. F. (1972). The Literature of the Second Self. University of Arizona Press.
Maack, L. H; Mullen, P. E. (1983). The Doppelgänger, Disintegration and Death: A Case Report. Psychological Medicine 13: 651-654.
Miller, K. (1985). Doubles: Studies in Literary History. Oxford University Press.
Rank, O. (1971, originally published in German, Der Doppelgänger, 1914). The Double: A Psychoanalytic Study. The University of North Carolina Press.
Reed, G. F. (1987). Doppelgänger. In Gregory R. L. The Oxford Companion to the Mind. Oxford University Press. pp. 200–201.
Todd, J; Dewhurst, K. (1962). The Significance of the Doppelgänger (Hallucinatory Double) in Folklore and Neuropsychiatry. Practitioner 188: 377-382.
Todd, J; Dewhurst, K. (1955). The Double: Its Psycho-Pathology and Psycho-Physiology. Journal of Nervous and Mental Disease 122: 47-55.
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