Justin Dillon, Meg Maguire, editor
McGraw-Hill, 2011
Buku Teks
Somerville, Ian
Cambridge Woodhead-Faulkner , 1990
Buku Teks
Gilg, Andrew
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Buku Teks
Compston, Hugh, 1955-, author
Palgrave Macmillan , 2009
Buku Teks
Pergamon Press, 1973
Buku Teks