Sheth, Jagdish N., author
Ohio South-Western Pub, 1989
Buku Teks
Czinkota, Michael R., author
The Dryden Press, 1996
Buku Teks
Keegan, Warren J., author
Pearson, 2011
Buku Teks
Keegan, Warren J., author
Prentice-Hall, 1999
Buku Teks
Keegan, Warren J., author
Prentice-Hall, 2000
Buku Teks