Johansson, Johny K., author
McGraw-Hill Irwin, 2003
Buku Teks
Keegan, Warren J., author
Prentice Hall International, 1989
Buku Teks
Keegan, Warren J., author
Prentice Hall International, 1995
Buku Teks
Dahringer, Lee D., author
Addison-Wesley, 1991
Buku Teks
Keegan, Warren J., author
Prentice-Hall, 1997
Buku Teks