London : St James Press, 1990,
Buku Referensi
Turabian, Kate L., author
University of Chicago Press, 1982
Buku Teks
Pugh, D.S.
Penguin Books, 1971
Buku Teks
Hope, A.D., author
Oxford University Press, 1992
Buku Teks
Buscemi, Santi V., author
McGraw-Hill , 2002
Buku Teks