McEwen, Abayomi, author
McGraw-hill Open Univer, 2011
Buku Teks
Gupta, Giri Raj, author
Allyn and Bacon, 1993
Buku Teks
edited by Glenys Parry and Fraser N. Watts
Routledge, 1996
Buku Teks
edited by Cleland, John; Ferry, Benoit [edited] (change)
The Falmer Press, 1995
Buku Teks
by Robert Desjarlais [and others]
Oxford University Press, 1995
Buku Teks