Amthor, T. K., Barrett, K., McBride, A., Ney-Grimm, J., Forton, G., & Tolkien, J. R. R. (1988). A spy in Isengard. Berkley Pub. Group.
Lua i Stíl Chicago (17ú heag.)Amthor, Terry K., Kevin Barrett, Angus McBride, Jessica Ney-Grimm, Gerald Forton, agus J. R. R. Tolkien. A Spy in Isengard. New York: Berkley Pub. Group, 1988.
Lua MLA (8ú heag.)Amthor, Terry K., et al. A Spy in Isengard. Berkley Pub. Group, 1988.
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