Lugton, Robert C.
Prentice-Hall, 1978
Buku Teks
Thomson, A.J.
Oxford Oxford University Press, 1986
Buku Teks
Hill, Robert J.
Macmillan, 1982
Buku Referensi
Steinberg, Roberta
Prentice-Hall, 1987
Buku Teks
Swan, Michael
Cambridge University Press, 1992
Buku Teks