Toynbee, Arnold J.
Oxford University Press, 1956
Buku Teks
Murdoch, James
Routledge , 1996
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McKay, John P.
Houghton Miffiln, 1984
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Mary Kupiec Cayton, Elliott J. Gorn, Peter W. Williams, editors
Charles Scribner's Sons, 1993
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Bailey, Thomas Andrew, 1902-1983
D.C. Heath, 1987
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