Thompson, June M.
Westview Press, 1990
Buku Teks
El-Agraa, Ali M
Prentice-Hall, 2001
Buku Teks
Nugent, Neill
Macmillan, 1994
Buku Teks
Chryssochoou, Dimitris N.
I.B. Tauris Publishers, 2000
Buku Teks
Folsom, Ralph Haughwout
West Group, 1995
Buku Teks