Burrus, Daniel
Harper Business , 1993
Buku Teks
Fransman, Martin
Cambridge University Press, 1991
Buku Teks
McIntyre, Anne
Judy Piatkus Publishers, 1997
Buku Teks
Engel, Beverly
John Wiley & Sons, 2005
Buku Teks
Oesch, Daniel
Oxford University Press, 2013
Buku Teks