Wilson, Thomas, author
Clarendon Press, 1984
Buku Teks
Auerbach, Robert D., author
Macmillan, 1989
Buku Teks
Stigum, Marcia
Illinois Dow Jones- Irwin , 1983
Buku Teks
Erhard, Ludwig, author
George Allen and Unwin, 1954
Buku Teks
Aaker, David A., author
John Wiley & Sons, 1984
Buku Teks