Press, Frank, author
W.H. Freeman and Company, 1986
Buku Referensi
Williams, Peter J
Longman, 1982
Buku Teks
Lisle, Richard J., author
Wiley-Blackwel, 2011
Buku Teks
Hiscock, Kevin. M.author
Wiley Blackwell, 2014
Buku Teks
Bates, Robert L., editors
Anchor Books, 1984
Buku Referensi