Thornton, A. P. (1977). Imperialism in the twentieth century. University of Minnesota Press.
Lua i Stíl Chicago (17ú heag.)Thornton, A. P. Imperialism in the Twentieth Century. Minneapolis: University of Minnesota Press, 1977.
Lua MLA (9ú heag.)Thornton, A. P. Imperialism in the Twentieth Century. University of Minnesota Press, 1977.
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