Trotter, David, author
Routledge, 1993
Buku Teks
Bull, John, author
Macmillan, 1991
Buku Teks
Karl, Frederick R., author
Farrar, Straus and Giroux, 1964
Buku Teks
Crosland, Margaret, author
Constable, 1981
Buku Teks
Larson, Jil, author
Cambridge University Press, 2009
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