Blackie Academic & Professional, 1995
Buku Teks
Waston, David
Falmer Press, 1998
Buku Teks
Donovan, John J.
Prentice-Hall, 1994
Buku Teks SO
edited by Georg Heeg ... [and others]
Prentice-Hall, 1992
Buku Referensi
Baron, David P.
Prentice-Hall, 2000
Buku Teks SO