Bowie, Fiona
BlackWell Publishing, 2005
Buku Teks
Firth, Raymond
Routledge, 1996
Buku Teks
edited by Peter Clarke and Stewart Sutherland
Routledge, 1991
Buku Teks
Toynbee, Arnold J.
Oxford University Press, 1956
Buku Teks
Stein, Rebecca L.
Pearson Education, 2005
Buku Teks