Russell, J. Thomas, author
Prentice-Hall, 1999
Buku Teks
Mooij, Marieke K. de, author
Prentice-Hall, 1991
Buku Teks
Kobliski, Kathy J, author
Entrepreneur Press, 2005
Buku Teks
Duffy, Ben
Prentice-Hall, 1957
Buku Teks
edited by John Philip Jones
Sage, 2000
Buku Teks