Britton, James N.
Cassell Educational Limited, 1993
Buku Teks
Eaglestone, Robert, author
Routledge , 2005
Buku Teks
Roberts, Edgar V., author
Prentice-Hall, 1977
Koleksi Publik
Headrick, Paul, 1957-, author
Wiley-Blackwell, 2014
Buku Teks
Cambridge University Press, 1997
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