edited by H.B. Thorelli
Penguin Books, 1973
Buku Teks
Cundiff, Edward W.
Prentice-Hall, 1988
Buku Teks
Majaro, Simon
George Allen & Uniwin, 1982
Buku Teks
Czinkota, Michael R.
The Dryden Press, 1996
Buku Teks
Keegan, Warren J.
Pearson , 2013
Buku Teks