Clear Light Publishers, 1999
Buku Teks
Routledge , 1996
Buku Teks
Gratton, Lynda, author
Financial Time Prentice Hall, 2000
Buku Teks
by Frank Minirth [and others]
Moody Press, 1990
Buku Teks
edited by Dharam Ghai and Jessica M. Vivian
Routledge, 1995
Buku Teks