Zettersten, A. (2011). J.R.R. Tolkien's double worlds and creative process: Language and life. Palgrave Macmillan.
Lua i Stíl Chicago (17ú heag.)Zettersten, Arne. J.R.R. Tolkien's Double Worlds and Creative Process: Language and Life. New York: Palgrave Macmillan, 2011.
Lua MLA (8ú heag.)Zettersten, Arne. J.R.R. Tolkien's Double Worlds and Creative Process: Language and Life. Palgrave Macmillan, 2011.
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