Simpson, A.W.B., author
Clarendon Press, 1986
Buku Teks
Thompson, Mark P., author
Sweet & Maxwell, 1995
Buku Teks
Curzon, L.B., author
Pitman, 1993
Buku Teks
Chappelle, Diane
Pearson, 1999
Buku Teks
Greenspan, Morris, author
University of California Press, 1959
Buku Teks