Christopher, Dawson, author
Catholic University of America Press, 20001
Buku Teks
Maple, James, author
John Murray, 1996
Buku Teks
Clough, Peter, author
Sage Publications, 2002
Buku Referensi
Yoshino, Kosaku, author
Routledge , 1992
Buku Teks
Koen Vermeir
Springer, 2012
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