Greenberg, Saul, author
Elsevier, 2012
Buku Teks
Eissen, Koos, author
Page one publishing pte ltd, 2011
Buku Teks
Resmini, Andrea, author
Elsevier, 2011
Buku Teks
Toynbee, Arnold J., translator
Osford University Press, 1969
Buku Teks
Handy, Richard, author
[Springer, ], 2012
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